From 613323a6a792f3dc6465a3b9f7b4aaa6c11cc1fb Mon Sep 17 00:00:00 2001
From: Andrew Purtell <apurtell@apache.org>
Date: Fri, 22 Jul 2022 15:07:18 -0700
Subject: [PATCH 1/3] HBASE-27203 Clean up error-prone findings in hbase-client

---
 .../hadoop/hbase/CatalogFamilyFormat.java     | 12 +--
 .../hadoop/hbase/ClientMetaTableAccessor.java | 59 ++++++-------
 .../org/apache/hadoop/hbase/ClusterId.java    |  1 +
 .../hadoop/hbase/ClusterMetricsBuilder.java   |  4 +-
 .../hadoop/hbase/CoprocessorEnvironment.java  |  4 +-
 .../hadoop/hbase/HBaseServerException.java    |  5 +-
 .../apache/hadoop/hbase/HRegionLocation.java  |  4 +-
 .../apache/hadoop/hbase/RegionLocations.java  |  2 +
 .../apache/hadoop/hbase/RegionMetrics.java    |  8 +-
 .../hadoop/hbase/ServerMetricsBuilder.java    | 19 ++--
 .../org/apache/hadoop/hbase/UserMetrics.java  |  4 +-
 .../hadoop/hbase/UserMetricsBuilder.java      |  4 +-
 .../hadoop/hbase/client/AbstractResponse.java |  6 +-
 .../AbstractRpcBasedConnectionRegistry.java   |  2 +-
 .../org/apache/hadoop/hbase/client/Admin.java | 14 ++-
 .../hbase/client/AdminOverAsyncAdmin.java     |  1 +
 .../apache/hadoop/hbase/client/Append.java    |  2 +-
 .../hadoop/hbase/client/AsyncAdmin.java       | 48 ++++-------
 .../AsyncAdminRequestRetryingCaller.java      |  3 -
 .../hadoop/hbase/client/AsyncTable.java       | 69 ++++++++-------
 ...talogReplicaLoadBalanceSimpleSelector.java | 10 ++-
 .../hadoop/hbase/client/CheckAndMutate.java   |  8 ++
 .../hbase/client/ClientIdGenerator.java       | 17 ++--
 .../hbase/client/ColumnFamilyDescriptor.java  | 26 +++---
 .../client/ColumnFamilyDescriptorBuilder.java | 65 ++++++--------
 .../hadoop/hbase/client/CompactType.java      |  6 +-
 .../apache/hadoop/hbase/client/Delete.java    |  4 +-
 .../org/apache/hadoop/hbase/client/Get.java   |  2 +-
 .../apache/hadoop/hbase/client/Increment.java |  1 +
 .../hadoop/hbase/client/IsolationLevel.java   |  7 +-
 .../hadoop/hbase/client/LogQueryFilter.java   |  5 +-
 .../MasterCoprocessorRpcChannelImpl.java      |  4 +-
 .../hadoop/hbase/client/MasterRegistry.java   |  4 +-
 .../hadoop/hbase/client/MultiResponse.java    |  6 +-
 .../hbase/client/MutableRegionInfo.java       |  1 +
 .../apache/hadoop/hbase/client/Mutation.java  | 19 ++--
 .../org/apache/hadoop/hbase/client/Put.java   |  1 +
 .../org/apache/hadoop/hbase/client/Query.java |  7 +-
 .../hbase/client/RawAsyncHBaseAdmin.java      | 86 +++++++++----------
 .../hbase/client/RawAsyncTableImpl.java       |  2 +-
 .../client/RegionCoprocessorServiceExec.java  |  2 +-
 .../hadoop/hbase/client/RegionInfo.java       | 33 +++----
 .../hbase/client/RegionReplicaUtil.java       |  4 +-
 ...RegionServerCoprocessorRpcChannelImpl.java |  4 +-
 .../apache/hadoop/hbase/client/Result.java    |  4 +-
 .../apache/hadoop/hbase/client/RowAccess.java |  1 -
 .../hadoop/hbase/client/RowMutations.java     |  2 +
 .../org/apache/hadoop/hbase/client/Scan.java  |  6 +-
 .../hbase/client/ScanResultConsumer.java      |  3 +-
 .../hadoop/hbase/client/ServiceCaller.java    |  8 +-
 .../hadoop/hbase/client/SlowLogParams.java    |  5 +-
 .../org/apache/hadoop/hbase/client/Table.java | 13 ++-
 .../hadoop/hbase/client/TableDescriptor.java  |  4 +-
 .../hbase/client/TableDescriptorBuilder.java  |  9 +-
 .../hbase/client/TableOverAsyncTable.java     | 16 ++--
 .../hadoop/hbase/client/TableState.java       | 18 ++--
 .../backoff/ClientBackoffPolicyFactory.java   |  4 -
 .../ExponentialClientBackoffPolicy.java       |  4 -
 .../BigDecimalColumnInterpreter.java          |  2 +-
 .../ReplicationPeerConfigUtil.java            | 32 +++----
 .../hbase/coprocessor/ColumnInterpreter.java  |  5 --
 .../exceptions/RegionOpeningException.java    |  4 +-
 .../hbase/filter/BigDecimalComparator.java    |  8 +-
 .../hadoop/hbase/filter/BinaryComparator.java | 18 ++--
 .../filter/BinaryComponentComparator.java     |  7 +-
 .../hbase/filter/BinaryPrefixComparator.java  | 18 ++--
 .../hadoop/hbase/filter/BitComparator.java    | 17 ++--
 .../hbase/filter/ColumnCountGetFilter.java    | 15 ++--
 .../hbase/filter/ColumnPaginationFilter.java  | 28 +++---
 .../hbase/filter/ColumnPrefixFilter.java      | 17 ++--
 .../hbase/filter/ColumnRangeFilter.java       | 10 +--
 .../hbase/filter/ColumnValueFilter.java       | 12 +--
 .../hadoop/hbase/filter/CompareFilter.java    | 12 ++-
 .../hbase/filter/DependentColumnFilter.java   | 16 ++--
 .../hadoop/hbase/filter/FamilyFilter.java     | 14 +--
 .../apache/hadoop/hbase/filter/Filter.java    |  1 -
 .../hadoop/hbase/filter/FilterList.java       | 15 ++--
 .../hbase/filter/FilterListWithAND.java       |  6 +-
 .../hadoop/hbase/filter/FilterListWithOR.java |  6 +-
 .../hbase/filter/FirstKeyOnlyFilter.java      | 21 +++--
 ...FirstKeyValueMatchingQualifiersFilter.java |  4 +-
 .../hadoop/hbase/filter/FuzzyRowFilter.java   | 26 +++---
 .../hbase/filter/InclusiveStopFilter.java     | 19 ++--
 .../hadoop/hbase/filter/KeyOnlyFilter.java    | 18 ++--
 .../hadoop/hbase/filter/LongComparator.java   | 14 ++-
 .../hbase/filter/MultiRowRangeFilter.java     | 19 ++--
 .../filter/MultipleColumnPrefixFilter.java    | 19 ++--
 .../hadoop/hbase/filter/NullComparator.java   | 18 ++--
 .../hadoop/hbase/filter/PageFilter.java       |  9 +-
 .../hadoop/hbase/filter/ParseFilter.java      |  5 +-
 .../hadoop/hbase/filter/PrefixFilter.java     | 17 ++--
 .../hadoop/hbase/filter/QualifierFilter.java  | 16 ++--
 .../hadoop/hbase/filter/RandomRowFilter.java  | 19 ++--
 .../hbase/filter/RegexStringComparator.java   | 17 ++--
 .../apache/hadoop/hbase/filter/RowFilter.java | 14 +--
 .../SingleColumnValueExcludeFilter.java       | 18 ++--
 .../hbase/filter/SingleColumnValueFilter.java |  5 +-
 .../hadoop/hbase/filter/SkipFilter.java       | 15 ++--
 .../hbase/filter/SubstringComparator.java     | 14 +--
 .../hadoop/hbase/filter/TimestampsFilter.java | 15 ++--
 .../hadoop/hbase/filter/ValueFilter.java      | 14 +--
 .../hadoop/hbase/filter/WhileMatchFilter.java | 17 ++--
 .../hadoop/hbase/filter/package-info.java     | 21 +++--
 .../hadoop/hbase/ipc/AbstractRpcClient.java   |  6 +-
 .../hbase/ipc/BlockingRpcConnection.java      |  7 +-
 .../hadoop/hbase/ipc/CellBlockBuilder.java    |  2 +
 .../apache/hadoop/hbase/ipc/ConnectionId.java | 16 ++--
 .../hadoop/hbase/ipc/HBaseRpcController.java  |  2 +
 .../hbase/ipc/NettyRpcDuplexHandler.java      |  9 +-
 .../apache/hadoop/hbase/ipc/RpcClient.java    |  4 +-
 .../hadoop/hbase/master/RegionState.java      |  7 +-
 .../hadoop/hbase/protobuf/ProtobufMagic.java  | 10 +--
 .../hadoop/hbase/quotas/QuotaRetriever.java   |  4 +-
 .../hbase/quotas/SpaceLimitSettings.java      |  4 +-
 .../hadoop/hbase/security/SaslUtil.java       |  8 +-
 .../security/access/AccessControlClient.java  | 56 +++++++-----
 .../security/access/AccessControlUtil.java    | 17 ++--
 .../access/ShadedAccessControlUtil.java       | 14 ++-
 .../security/access/TablePermission.java      |  4 +-
 ...tractSaslClientAuthenticationProvider.java |  1 +
 .../security/visibility/VisibilityClient.java | 10 ++-
 .../hbase/shaded/protobuf/ProtobufUtil.java   | 28 ++----
 .../shaded/protobuf/RequestConverter.java     | 13 +--
 .../apache/hadoop/hbase/util/Writables.java   |  1 +
 .../hbase/zookeeper/ReadOnlyZKClient.java     |  4 +
 .../hadoop/hbase/zookeeper/ZKMetadata.java    |  2 +-
 .../client/TestAsyncTableRpcPriority.java     | 14 +--
 .../hbase/client/TestAsyncTableTracing.java   | 14 +--
 .../client/TestCoprocessorDescriptor.java     |  4 -
 .../apache/hadoop/hbase/client/TestGet.java   |  3 +-
 .../hadoop/hbase/client/TestMutation.java     | 10 +--
 .../hbase/client/TestRegionInfoDisplay.java   |  4 +-
 .../apache/hadoop/hbase/client/TestScan.java  | 33 +++----
 .../client/TestSimpleRequestController.java   |  7 +-
 .../hbase/filter/TestKeyOnlyFilter.java       |  4 +-
 .../hbase/ipc/TestCellBlockBuilder.java       |  9 +-
 .../hbase/ipc/TestNettyRpcConnection.java     |  4 +-
 .../TestQuotaGlobalsSettingsBypass.java       |  1 +
 .../security/TestHBaseSaslRpcClient.java      | 29 +++----
 .../hbase/util/TestRoundRobinPoolMap.java     |  6 +-
 .../hbase/util/TestThreadLocalPoolMap.java    |  6 +-
 141 files changed, 881 insertions(+), 825 deletions(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/CatalogFamilyFormat.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/CatalogFamilyFormat.java
index d714c47359b9..c2385084a3ea 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/CatalogFamilyFormat.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/CatalogFamilyFormat.java
@@ -349,8 +349,8 @@ public static TableState getTableState(Result r) throws IOException {
   }
 
   /**
-   * @return Deserialized values of &lt;qualifier,regioninfo&gt; pairs taken from column values that
-   *         match the regex 'info:merge.*' in array of <code>cells</code>.
+   * Returns Deserialized values of &lt;qualifier,regioninfo&gt; pairs taken from column values that
+   * match the regex 'info:merge.*' in array of <code>cells</code>.
    */
   @Nullable
   public static Map<String, RegionInfo> getMergeRegionsWithName(Cell[] cells) {
@@ -376,8 +376,8 @@ public static Map<String, RegionInfo> getMergeRegionsWithName(Cell[] cells) {
   }
 
   /**
-   * @return Deserialized regioninfo values taken from column values that match the regex
-   *         'info:merge.*' in array of <code>cells</code>.
+   * Returns Deserialized regioninfo values taken from column values that match the regex
+   * 'info:merge.*' in array of <code>cells</code>.
    */
   @Nullable
   public static List<RegionInfo> getMergeRegions(Cell[] cells) {
@@ -386,8 +386,8 @@ public static List<RegionInfo> getMergeRegions(Cell[] cells) {
   }
 
   /**
-   * @return True if any merge regions present in <code>cells</code>; i.e. the column in
-   *         <code>cell</code> matches the regex 'info:merge.*'.
+   * Returns True if any merge regions present in <code>cells</code>; i.e. the column in
+   * <code>cell</code> matches the regex 'info:merge.*'.
    */
   public static boolean hasMergeRegions(Cell[] cells) {
     for (Cell cell : cells) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClientMetaTableAccessor.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClientMetaTableAccessor.java
index b75398dd1cf9..42bfd757e0d1 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClientMetaTableAccessor.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClientMetaTableAccessor.java
@@ -59,6 +59,7 @@ private ClientMetaTableAccessor() {
   }
 
   @InterfaceAudience.Private
+  @SuppressWarnings("ImmutableEnumChecker")
   public enum QueryType {
     ALL(HConstants.TABLE_FAMILY, HConstants.CATALOG_FAMILY),
     REGION(HConstants.CATALOG_FAMILY),
@@ -100,11 +101,7 @@ public static CompletableFuture<Optional<TableState>> getTableState(AsyncTable<?
     return future;
   }
 
-  /**
-   * Returns the HRegionLocation from meta for the given region n * @param regionName region we're
-   * looking for
-   * @return HRegionLocation for the given region
-   */
+  /** Returns the HRegionLocation from meta for the given region */
   public static CompletableFuture<Optional<HRegionLocation>>
     getRegionLocation(AsyncTable<?> metaTable, byte[] regionName) {
     CompletableFuture<Optional<HRegionLocation>> future = new CompletableFuture<>();
@@ -126,11 +123,7 @@ public static CompletableFuture<Optional<TableState>> getTableState(AsyncTable<?
     return future;
   }
 
-  /**
-   * Returns the HRegionLocation from meta for the given encoded region name n * @param
-   * encodedRegionName region we're looking for
-   * @return HRegionLocation for the given region
-   */
+  /** Returns the HRegionLocation from meta for the given encoded region name */
   public static CompletableFuture<Optional<HRegionLocation>>
     getRegionLocationWithEncodedName(AsyncTable<?> metaTable, byte[] encodedRegionName) {
     CompletableFuture<Optional<HRegionLocation>> future = new CompletableFuture<>();
@@ -167,8 +160,9 @@ private static Optional<TableState> getTableState(Result r) throws IOException {
   }
 
   /**
-   * Used to get all region locations for the specific table. n * @param tableName table we're
-   * looking for, can be null for getting all regions
+   * Used to get all region locations for the specific table
+   * @param metaTable scanner over meta table
+   * @param tableName table we're looking for, can be null for getting all regions
    * @return the list of region locations. The return value will be wrapped by a
    *         {@link CompletableFuture}.
    */
@@ -191,8 +185,9 @@ public static CompletableFuture<List<HRegionLocation>> getTableHRegionLocations(
   }
 
   /**
-   * Used to get table regions' info and server. n * @param tableName table we're looking for, can
-   * be null for getting all regions
+   * Used to get table regions' info and server.
+   * @param metaTable                   scanner over meta table
+   * @param tableName                   table we're looking for, can be null for getting all regions
    * @param excludeOfflinedSplitParents don't return split parents
    * @return the list of regioninfos and server. The return value will be wrapped by a
    *         {@link CompletableFuture}.
@@ -221,9 +216,11 @@ private static CompletableFuture<List<Pair<RegionInfo, ServerName>>> getTableReg
   }
 
   /**
-   * Performs a scan of META table for given table. n * @param tableName table withing we scan
-   * @param type    scanned part of meta
-   * @param visitor Visitor invoked against each row
+   * Performs a scan of META table for given table.
+   * @param metaTable scanner over meta table
+   * @param tableName table within we scan
+   * @param type      scanned part of meta
+   * @param visitor   Visitor invoked against each row
    */
   private static CompletableFuture<Void> scanMeta(AsyncTable<AdvancedScanResultConsumer> metaTable,
     TableName tableName, QueryType type, final Visitor visitor) {
@@ -232,11 +229,13 @@ private static CompletableFuture<Void> scanMeta(AsyncTable<AdvancedScanResultCon
   }
 
   /**
-   * Performs a scan of META table for given table. n * @param startRow Where to start the scan
-   * @param stopRow Where to stop the scan
-   * @param type    scanned part of meta
-   * @param maxRows maximum rows to return
-   * @param visitor Visitor invoked against each row
+   * Performs a scan of META table for given table.
+   * @param metaTable scanner over meta table
+   * @param startRow  Where to start the scan
+   * @param stopRow   Where to stop the scan
+   * @param type      scanned part of meta
+   * @param maxRows   maximum rows to return
+   * @param visitor   Visitor invoked against each row
    */
   private static CompletableFuture<Void> scanMeta(AsyncTable<AdvancedScanResultConsumer> metaTable,
     byte[] startRow, byte[] stopRow, QueryType type, int maxRows, final Visitor visitor) {
@@ -456,19 +455,12 @@ private static Scan getMetaScan(AsyncTable<?> metaTable, int rowUpperLimit) {
     return scan;
   }
 
-  /**
-   * Returns an HRegionLocationList extracted from the result.
-   * @return an HRegionLocationList containing all locations for the region range or null if we
-   *         can't deserialize the result.
-   */
+  /** Returns an HRegionLocationList extracted from the result. */
   private static Optional<RegionLocations> getRegionLocations(Result r) {
     return Optional.ofNullable(CatalogFamilyFormat.getRegionLocations(r));
   }
 
-  /**
-   * @param tableName table we're working with
-   * @return start row for scanning META according to query type
-   */
+  /** Returns start row for scanning META according to query type */
   public static byte[] getTableStartRowForMeta(TableName tableName, QueryType type) {
     if (tableName == null) {
       return null;
@@ -490,10 +482,7 @@ public static byte[] getTableStartRowForMeta(TableName tableName, QueryType type
     }
   }
 
-  /**
-   * @param tableName table we're working with
-   * @return stop row for scanning META according to query type
-   */
+  /** Returns stop row for scanning META according to query type */
   public static byte[] getTableStopRowForMeta(TableName tableName, QueryType type) {
     if (tableName == null) {
       return null;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterId.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterId.java
index 9b7a5de19bd3..8c675c4522e6 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterId.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterId.java
@@ -51,6 +51,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse the serialized representation of the {@link ClusterId}
    * @param bytes A pb serialized {@link ClusterId} instance with pb magic prefix
    * @return An instance of {@link ClusterId} made from <code>bytes</code> n * @see #toByteArray()
    */
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterMetricsBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterMetricsBuilder.java
index 5695f5b65ade..7254209487b2 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterMetricsBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ClusterMetricsBuilder.java
@@ -67,13 +67,13 @@ public static ClusterStatusProtos.ClusterStatus toClusterStatus(ClusterMetrics m
           .collect(Collectors.toList()))
         .addAllTableRegionStatesCount(metrics.getTableRegionStatesCount().entrySet().stream()
           .map(status -> ClusterStatusProtos.TableRegionStatesCount.newBuilder()
-            .setTableName(ProtobufUtil.toProtoTableName((status.getKey())))
+            .setTableName(ProtobufUtil.toProtoTableName(status.getKey()))
             .setRegionStatesCount(ProtobufUtil.toTableRegionStatesCount(status.getValue())).build())
           .collect(Collectors.toList()))
         .addAllDecommissionedServers(metrics.getDecommissionedServerNames().stream()
           .map(ProtobufUtil::toServerName).collect(Collectors.toList()));
     if (metrics.getMasterName() != null) {
-      builder.setMaster(ProtobufUtil.toServerName((metrics.getMasterName())));
+      builder.setMaster(ProtobufUtil.toServerName(metrics.getMasterName()));
     }
     if (metrics.getMasterTasks() != null) {
       builder.addAllMasterTasks(metrics.getMasterTasks().stream()
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/CoprocessorEnvironment.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/CoprocessorEnvironment.java
index 94909f1c14ef..32e06d610247 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/CoprocessorEnvironment.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/CoprocessorEnvironment.java
@@ -44,8 +44,8 @@ public interface CoprocessorEnvironment<C extends Coprocessor> {
   int getLoadSequence();
 
   /**
-   * @return a Read-only Configuration; throws {@link UnsupportedOperationException} if you try to
-   *         set a configuration.
+   * Returns a Read-only Configuration; throws {@link UnsupportedOperationException} if you try to
+   * set a configuration.
    */
   Configuration getConfiguration();
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/HBaseServerException.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/HBaseServerException.java
index 3484995c1bfd..47a86f9492f5 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/HBaseServerException.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/HBaseServerException.java
@@ -44,10 +44,7 @@ public HBaseServerException(boolean serverOverloaded, String message) {
     this.serverOverloaded = serverOverloaded;
   }
 
-  /**
-   * @param t throwable to check for server overloaded state
-   * @return True if the server was considered overloaded when the exception was thrown
-   */
+  /** Returns True if the server was considered overloaded when the exception was thrown */
   public static boolean isServerOverloaded(Throwable t) {
     if (t instanceof HBaseServerException) {
       return ((HBaseServerException) t).isServerOverloaded();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionLocation.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionLocation.java
index 0decb58bc20b..ebf6d919374d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionLocation.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/HRegionLocation.java
@@ -100,8 +100,8 @@ public long getSeqNum() {
   }
 
   /**
-   * @return String made of hostname and port formatted as per
-   *         {@link Addressing#createHostAndPortStr(String, int)}
+   * Returns String made of hostname and port formatted as per
+   * {@link Addressing#createHostAndPortStr(String, int)}
    */
   public String getHostnamePort() {
     return Addressing.createHostAndPortStr(this.getHostname(), this.getPort());
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
index 4d6dd6d43fa3..4c0390c6c3be 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
@@ -208,6 +208,7 @@ public RegionLocations removeElementsWithNullLocation() {
    * @param other the locations to merge with
    * @return an RegionLocations object with merged locations or the same object if nothing is merged
    */
+  @SuppressWarnings("ReferenceEquality")
   public RegionLocations mergeLocations(RegionLocations other) {
     assert other != null;
 
@@ -280,6 +281,7 @@ private HRegionLocation selectRegionLocation(HRegionLocation oldLocation,
    * @return an RegionLocations object with updated locations or the same object if nothing is
    *         updated
    */
+  @SuppressWarnings("ReferenceEquality")
   public RegionLocations updateLocation(HRegionLocation location, boolean checkForEquals,
     boolean force) {
     assert location != null;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionMetrics.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionMetrics.java
index 88527e86442c..47b36a7a1516 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionMetrics.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionMetrics.java
@@ -53,8 +53,8 @@ public interface RegionMetrics {
   public long getCpRequestCount();
 
   /**
-   * @return the number of write requests and read requests and coprocessor service requests made to
-   *         region
+   * Returns the number of write requests and read requests and coprocessor service requests made to
+   * region
    */
   default long getRequestCount() {
     return getReadRequestCount() + getWriteRequestCount() + getCpRequestCount();
@@ -113,8 +113,8 @@ default String getNameAsString() {
   int getStoreRefCount();
 
   /**
-   * @return the max reference count for any store file among all compacted stores files of this
-   *         region
+   * Returns the max reference count for any store file among all compacted stores files of this
+   * region
    */
   int getMaxCompactedStoreFileRefCount();
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ServerMetricsBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ServerMetricsBuilder.java
index 99f8520aa362..7a0312f22fdc 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ServerMetricsBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ServerMetricsBuilder.java
@@ -44,10 +44,6 @@
 @InterfaceAudience.Private
 public final class ServerMetricsBuilder {
 
-  /**
-   * @param sn the server name
-   * @return a empty metrics
-   */
   public static ServerMetrics of(ServerName sn) {
     return newBuilder(sn).build();
   }
@@ -300,6 +296,7 @@ public int getVersionNumber() {
       return versionNumber;
     }
 
+    @Override
     public String getVersion() {
       return version;
     }
@@ -414,16 +411,18 @@ public String toString() {
         int currentMaxCompactedStoreFileRefCount = r.getMaxCompactedStoreFileRefCount();
         maxCompactedStoreFileRefCount =
           Math.max(maxCompactedStoreFileRefCount, currentMaxCompactedStoreFileRefCount);
-        uncompressedStoreFileSizeMB += r.getUncompressedStoreFileSize().get(Size.Unit.MEGABYTE);
-        storeFileSizeMB += r.getStoreFileSize().get(Size.Unit.MEGABYTE);
-        memStoreSizeMB += r.getMemStoreSize().get(Size.Unit.MEGABYTE);
-        storefileIndexSizeKB += r.getStoreFileUncompressedDataIndexSize().get(Size.Unit.KILOBYTE);
+        uncompressedStoreFileSizeMB +=
+          (long) r.getUncompressedStoreFileSize().get(Size.Unit.MEGABYTE);
+        storeFileSizeMB += (long) r.getStoreFileSize().get(Size.Unit.MEGABYTE);
+        memStoreSizeMB += (long) r.getMemStoreSize().get(Size.Unit.MEGABYTE);
+        storefileIndexSizeKB +=
+          (long) r.getStoreFileUncompressedDataIndexSize().get(Size.Unit.KILOBYTE);
         readRequestsCount += r.getReadRequestCount();
         cpRequestsCount += r.getCpRequestCount();
         writeRequestsCount += r.getWriteRequestCount();
         filteredReadRequestsCount += r.getFilteredReadRequestCount();
-        rootLevelIndexSizeKB += r.getStoreFileRootLevelIndexSize().get(Size.Unit.KILOBYTE);
-        bloomFilterSizeMB += r.getBloomFilterSize().get(Size.Unit.MEGABYTE);
+        rootLevelIndexSizeKB += (long) r.getStoreFileRootLevelIndexSize().get(Size.Unit.KILOBYTE);
+        bloomFilterSizeMB += (long) r.getBloomFilterSize().get(Size.Unit.MEGABYTE);
         compactedCellCount += r.getCompactedCellCount();
         compactingCellCount += r.getCompactingCellCount();
       }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetrics.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetrics.java
index 05108c70e746..681b1f416c78 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetrics.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetrics.java
@@ -50,8 +50,8 @@ interface ClientMetrics {
   long getWriteRequestCount();
 
   /**
-   * @return the number of write requests and read requests and coprocessor service requests made by
-   *         the user
+   * Returns the number of write requests and read requests and coprocessor service requests made by
+   * the user
    */
   default long getRequestCount() {
     return getReadRequestCount() + getWriteRequestCount();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetricsBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetricsBuilder.java
index ab63f19fec85..4a66283146d9 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetricsBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/UserMetricsBuilder.java
@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hbase;
 
+import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 import org.apache.hadoop.hbase.util.Strings;
@@ -30,7 +31,8 @@
 public final class UserMetricsBuilder {
 
   public static UserMetrics toUserMetrics(ClusterStatusProtos.UserLoad userLoad) {
-    UserMetricsBuilder builder = UserMetricsBuilder.newBuilder(userLoad.getUserName().getBytes());
+    UserMetricsBuilder builder =
+      UserMetricsBuilder.newBuilder(userLoad.getUserName().getBytes(StandardCharsets.UTF_8));
     userLoad.getClientMetricsList().stream()
       .map(clientMetrics -> new ClientMetricsImpl(clientMetrics.getHostName(),
         clientMetrics.getReadRequestsCount(), clientMetrics.getWriteRequestsCount(),
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractResponse.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractResponse.java
index bb44defbac6a..b0a33eda4021 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractResponse.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractResponse.java
@@ -27,11 +27,9 @@ abstract class AbstractResponse {
 
   public enum ResponseType {
 
-    SINGLE(0),
-    MULTI(1);
+    SINGLE,
+    MULTI;
 
-    ResponseType(int value) {
-    }
   }
 
   public abstract ResponseType type();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractRpcBasedConnectionRegistry.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractRpcBasedConnectionRegistry.java
index 2380335e56b0..6dd14a520ee4 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractRpcBasedConnectionRegistry.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AbstractRpcBasedConnectionRegistry.java
@@ -135,7 +135,7 @@ private void populateStubs(Set<ServerName> addrs) throws IOException {
    * Typically, you can use lambda expression to implement this interface as
    *
    * <pre>
-   * (c, s, d) -> s.xxx(c, your request here, d)
+   * (c, s, d) -&gt; s.xxx(c, your request here, d)
    * </pre>
    */
   @FunctionalInterface
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
index 96923ae84621..34f7cf43308a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
@@ -115,6 +115,7 @@ public interface Admin extends Abortable, Closeable {
   Connection getConnection();
 
   /**
+   * Check if a table exists.
    * @param tableName Table to check.
    * @return <code>true</code> if table exists already.
    * @throws IOException if a remote or network exception occurs
@@ -187,7 +188,7 @@ default TableName[] listTableNames(Pattern pattern) throws IOException {
    * Get a table descriptor.
    * @param tableName as a {@link TableName}
    * @return the tableDescriptor
-   * @throws org.apache.hadoop.hbase.TableNotFoundException
+   * @throws org.apache.hadoop.hbase.TableNotFoundException if the table was not found
    * @throws IOException                                    if a remote or network exception occurs
    */
   TableDescriptor getDescriptor(TableName tableName) throws TableNotFoundException, IOException;
@@ -381,6 +382,7 @@ default void disableTable(TableName tableName) throws IOException {
   }
 
   /**
+   * Check if a table is enabled.
    * @param tableName name of table to check
    * @return <code>true</code> if table is on-line
    * @throws IOException if a remote or network exception occurs
@@ -388,6 +390,7 @@ default void disableTable(TableName tableName) throws IOException {
   boolean isTableEnabled(TableName tableName) throws IOException;
 
   /**
+   * Check if a table is disabled.
    * @param tableName name of table to check
    * @return <code>true</code> if table is off-line
    * @throws IOException if a remote or network exception occurs
@@ -395,6 +398,7 @@ default void disableTable(TableName tableName) throws IOException {
   boolean isTableDisabled(TableName tableName) throws IOException;
 
   /**
+   * Check if a table is available.
    * @param tableName name of table to check
    * @return <code>true</code> if all regions of the table are available
    * @throws IOException if a remote or network exception occurs
@@ -1100,6 +1104,7 @@ default ClusterMetrics getClusterMetrics() throws IOException {
   ClusterMetrics getClusterMetrics(EnumSet<Option> options) throws IOException;
 
   /**
+   * Get the current active master.
    * @return current master server name
    * @throws IOException if a remote or network exception occurs
    */
@@ -1108,6 +1113,7 @@ default ServerName getMaster() throws IOException {
   }
 
   /**
+   * Get a list of current backup masters.
    * @return current backup master list
    * @throws IOException if a remote or network exception occurs
    */
@@ -1116,6 +1122,7 @@ default Collection<ServerName> getBackupMasters() throws IOException {
   }
 
   /**
+   * Get the live server list.
    * @return current live region servers list
    * @throws IOException if a remote or network exception occurs
    */
@@ -1224,7 +1231,7 @@ default void deleteNamespace(String name) throws IOException {
    * Get a namespace descriptor by name.
    * @param name name of namespace descriptor
    * @return A descriptor
-   * @throws org.apache.hadoop.hbase.NamespaceNotFoundException
+   * @throws org.apache.hadoop.hbase.NamespaceNotFoundException if the namespace was not found
    * @throws IOException                                        if a remote or network exception
    *                                                            occurs
    */
@@ -1338,7 +1345,8 @@ Future<Boolean> abortProcedureAsync(long procId, boolean mayInterruptIfRunning)
    * @param serverName The servername of the regionserver.
    * @throws IOException                                                      if a remote or network
    *                                                                          exception occurs
-   * @throws org.apache.hadoop.hbase.regionserver.wal.FailedLogCloseException
+   * @throws org.apache.hadoop.hbase.regionserver.wal.FailedLogCloseException if we failed to close
+   *                                                                          the WAL
    */
   void rollWALWriter(ServerName serverName) throws IOException, FailedLogCloseException;
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
index efab24904622..9e2b990d91c1 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
@@ -379,6 +379,7 @@ public boolean balancerSwitch(boolean onOrOff, boolean synchronous) throws IOExc
     return get(admin.balancerSwitch(onOrOff, synchronous));
   }
 
+  @Override
   public BalanceResponse balance(BalanceRequest request) throws IOException {
     return get(admin.balance(request));
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
index 76e923d39863..9c1dbd0922c6 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
@@ -49,7 +49,7 @@
 @InterfaceAudience.Public
 public class Append extends Mutation {
   private static final Logger LOG = LoggerFactory.getLogger(Append.class);
-  private static final long HEAP_OVERHEAD = ClassSize.REFERENCE + ClassSize.TIMERANGE;
+  private static final long HEAP_OVERHEAD = (long) (ClassSize.REFERENCE + ClassSize.TIMERANGE);
   private TimeRange tr = TimeRange.allTime();
 
   /**
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
index 996410d26f5a..18a449e40083 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
@@ -66,6 +66,7 @@
 public interface AsyncAdmin {
 
   /**
+   * Check if a table exists.
    * @param tableName Table to check.
    * @return True if table exists already. The return value will be wrapped by a
    *         {@link CompletableFuture}.
@@ -215,6 +216,7 @@ CompletableFuture<Void> createTable(TableDescriptor desc, byte[] startKey, byte[
   CompletableFuture<Void> disableTable(TableName tableName);
 
   /**
+   * Check if a table is enabled.
    * @param tableName name of table to check
    * @return true if table is on-line. The return value will be wrapped by a
    *         {@link CompletableFuture}.
@@ -222,6 +224,7 @@ CompletableFuture<Void> createTable(TableDescriptor desc, byte[] startKey, byte[
   CompletableFuture<Boolean> isTableEnabled(TableName tableName);
 
   /**
+   * Check if a table is disabled.
    * @param tableName name of table to check
    * @return true if table is off-line. The return value will be wrapped by a
    *         {@link CompletableFuture}.
@@ -229,6 +232,7 @@ CompletableFuture<Void> createTable(TableDescriptor desc, byte[] startKey, byte[
   CompletableFuture<Boolean> isTableDisabled(TableName tableName);
 
   /**
+   * Check if a table is available.
    * @param tableName name of table to check
    * @return true if all regions of the table are available. The return value will be wrapped by a
    *         {@link CompletableFuture}.
@@ -591,11 +595,15 @@ default CompletableFuture<Void> mergeRegions(byte[] nameOfRegionA, byte[] nameOf
   CompletableFuture<Void> splitRegion(byte[] regionName, byte[] splitPoint);
 
   /**
+   * Assign an individual region.
    * @param regionName Encoded or full name of region to assign.
    */
   CompletableFuture<Void> assign(byte[] regionName);
 
   /**
+   * Unassign a region from current hosting regionserver. Region will then be assigned to a
+   * regionserver chosen at random. Region could be reassigned back to the same server. Use
+   * {@link #move(byte[], ServerName)} if you want to control the region movement.
    * @param regionName Encoded or full name of region to unassign.
    */
   CompletableFuture<Void> unassign(byte[] regionName);
@@ -1183,19 +1191,21 @@ default CompletableFuture<Integer> getMasterInfoPort() {
   CompletableFuture<Void> rollWALWriter(ServerName serverName);
 
   /**
-   * Clear compacting queues on a region server. n * @param queues the set of queue name
+   * Clear compacting queues on a region server.
+   * @param serverName The servername of the region server.
+   * @param queues     the set of queue name
    */
   CompletableFuture<Void> clearCompactionQueues(ServerName serverName, Set<String> queues);
 
   /**
-   * Get a list of {@link RegionMetrics} of all regions hosted on a region seerver. n * @return a
-   * list of {@link RegionMetrics} wrapped by {@link CompletableFuture}
+   * Get a list of {@link RegionMetrics} of all regions hosted on a region server.
+   * @return list of {@link RegionMetrics} wrapped by {@link CompletableFuture}
    */
   CompletableFuture<List<RegionMetrics>> getRegionMetrics(ServerName serverName);
 
   /**
-   * Get a list of {@link RegionMetrics} of all regions hosted on a region seerver for a table. nn
-   * * @return a list of {@link RegionMetrics} wrapped by {@link CompletableFuture}
+   * Get a list of {@link RegionMetrics} of all regions hosted on a region server for a table.
+   * @return a list of {@link RegionMetrics} wrapped by {@link CompletableFuture}
    */
   CompletableFuture<List<RegionMetrics>> getRegionMetrics(ServerName serverName,
     TableName tableName);
@@ -1256,8 +1266,8 @@ CompletableFuture<CompactionState> getCompactionState(TableName tableName,
   CompletableFuture<Optional<Long>> getLastMajorCompactionTimestampForRegion(byte[] regionName);
 
   /**
-   * @return the list of supported security capabilities. The return value will be wrapped by a
-   *         {@link CompletableFuture}.
+   * Returns the list of supported security capabilities. The return value will be wrapped by a
+   * {@link CompletableFuture}.
    */
   CompletableFuture<List<SecurityCapability>> getSecurityCapabilities();
 
@@ -1401,9 +1411,7 @@ default CompletableFuture<Boolean> normalize() {
    * one line lambda expression, like:
    *
    * <pre>
-   * <code>
-   * channel -> xxxService.newStub(channel)
-   * </code>
+   * channel -&gt; xxxService.newStub(channel)
    * </pre>
    *
    * @param stubMaker a delegation to the actual {@code newStub} call.
@@ -1424,9 +1432,7 @@ <S, R> CompletableFuture<R> coprocessorService(Function<RpcChannel, S> stubMaker
    * one line lambda expression, like:
    *
    * <pre>
-   * <code>
-   * channel -> xxxService.newStub(channel)
-   * </code>
+   * channel -&gt; xxxService.newStub(channel)
    * </pre>
    *
    * @param stubMaker  a delegation to the actual {@code newStub} call.
@@ -1635,7 +1641,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
   /**
    * Creates a new RegionServer group with the given name
    * @param groupName the name of the group
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> addRSGroup(String groupName);
 
@@ -1643,34 +1648,29 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * Get group info for the given group name
    * @param groupName the group name
    * @return group info
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<RSGroupInfo> getRSGroup(String groupName);
 
   /**
    * Get group info for the given hostPort
    * @param hostPort HostPort to get RSGroupInfo for
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<RSGroupInfo> getRSGroup(Address hostPort);
 
   /**
    * Get group info for the given table
    * @param tableName table name to get RSGroupInfo for
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<RSGroupInfo> getRSGroup(TableName tableName);
 
   /**
    * Lists current set of RegionServer groups
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<List<RSGroupInfo>> listRSGroups();
 
   /**
    * Get all tables in this RegionServer group.
    * @param groupName the group name
-   * @throws IOException if a remote or network exception occurs
    * @see #getConfiguredNamespacesAndTablesInRSGroup(String)
    */
   CompletableFuture<List<TableName>> listTablesInRSGroup(String groupName);
@@ -1685,7 +1685,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * in the group 'A', but this method will not return these tables but only the namespace 'nsA',
    * while the {@link #listTablesInRSGroup(String)} will return all these tables.
    * @param groupName the group name
-   * @throws IOException if a remote or network exception occurs
    * @see #listTablesInRSGroup(String)
    */
   CompletableFuture<Pair<List<String>, List<TableName>>>
@@ -1694,7 +1693,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
   /**
    * Remove RegionServer group associated with the given name
    * @param groupName the group name
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> removeRSGroup(String groupName);
 
@@ -1704,7 +1702,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * servers to join other clusters. So we need to remove these servers from the group. 2.
    * Dead/recovering/live servers will be disallowed.
    * @param servers set of servers to remove
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> removeServersFromRSGroup(Set<Address> servers);
 
@@ -1712,7 +1709,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * Move given set of servers to the specified target RegionServer group
    * @param servers   set of servers to move
    * @param groupName the group to move servers to
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> moveServersToRSGroup(Set<Address> servers, String groupName);
 
@@ -1720,7 +1716,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * Set the RegionServer group for tables
    * @param tables    tables to set group for
    * @param groupName group name for tables
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> setRSGroup(Set<TableName> tables, String groupName);
 
@@ -1728,7 +1723,6 @@ default CompletableFuture<List<Boolean>> hasUserPermissions(List<Permission> per
    * Balance regions in the given RegionServer group
    * @param groupName the group name
    * @return BalanceResponse details about the balancer run
-   * @throws IOException if a remote or network exception occurs
    */
   default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
     return balanceRSGroup(groupName, BalanceRequest.defaultInstance());
@@ -1739,7 +1733,6 @@ default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
    * @param groupName the group name
    * @param request   options to define how the balancer should run
    * @return BalanceResponse details about the balancer run
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<BalanceResponse> balanceRSGroup(String groupName, BalanceRequest request);
 
@@ -1747,7 +1740,6 @@ default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
    * Rename rsgroup
    * @param oldName old rsgroup name
    * @param newName new rsgroup name
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> renameRSGroup(String oldName, String newName);
 
@@ -1755,7 +1747,6 @@ default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
    * Update RSGroup configuration
    * @param groupName     the group name
    * @param configuration new configuration of the group name to be set
-   * @throws IOException if a remote or network exception occurs
    */
   CompletableFuture<Void> updateRSGroupConfig(String groupName, Map<String, String> configuration);
 
@@ -1769,7 +1760,6 @@ default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
    * @param serverType   enum for server type: HMaster or RegionServer
    * @param limit        put a limit to list of records that server should send in response
    * @param filterParams additional filter params
-   * @return Log entries representing online records from servers
    */
   CompletableFuture<List<LogEntry>> getLogEntries(Set<ServerName> serverNames, String logType,
     ServerType serverType, int limit, Map<String, Object> filterParams);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdminRequestRetryingCaller.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdminRequestRetryingCaller.java
index de6e967f21c4..d3bec8b3cfbf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdminRequestRetryingCaller.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdminRequestRetryingCaller.java
@@ -29,9 +29,6 @@
 
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.AdminService;
 
-/**
- * @since 2.0.0
- */
 @InterfaceAudience.Private
 public class AsyncAdminRequestRetryingCaller<T> extends AsyncRpcRetryingCaller<T> {
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncTable.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncTable.java
index b9a439f067bf..3c03444cfbbc 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncTable.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncTable.java
@@ -223,16 +223,14 @@ default CompletableFuture<Long> incrementColumnValue(byte[] row, byte[] family,
    * This is a fluent style API, the code is like:
    *
    * <pre>
-   * <code>
    * table.checkAndMutate(row, family).qualifier(qualifier).ifNotExists().thenPut(put)
-   *     .thenAccept(succ -> {
-   *       if (succ) {
-   *         System.out.println("Check and put succeeded");
-   *       } else {
-   *         System.out.println("Check and put failed");
-   *       }
-   *     });
-   * </code>
+   *   .thenAccept(succ -&gt; {
+   *     if (succ) {
+   *       System.out.println("Check and put succeeded");
+   *     } else {
+   *       System.out.println("Check and put failed");
+   *     }
+   *   });
    * </pre>
    *
    * @deprecated Since 3.0.0, will be removed in 4.0.0. For internal test use only, do not use it
@@ -250,11 +248,13 @@ default CompletableFuture<Long> incrementColumnValue(byte[] row, byte[] family,
   interface CheckAndMutateBuilder {
 
     /**
+     * Match a qualifier.
      * @param qualifier column qualifier to check.
      */
     CheckAndMutateBuilder qualifier(byte[] qualifier);
 
     /**
+     * Match a timerange.
      * @param timeRange time range to check.
      */
     CheckAndMutateBuilder timeRange(TimeRange timeRange);
@@ -273,12 +273,14 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
     }
 
     /**
+     * Compare a value
      * @param compareOp comparison operator to use
      * @param value     the expected value
      */
     CheckAndMutateBuilder ifMatches(CompareOperator compareOp, byte[] value);
 
     /**
+     * Specify a Put to commit if the check succeeds.
      * @param put data to put if check succeeds
      * @return {@code true} if the new put was executed, {@code false} otherwise. The return value
      *         will be wrapped by a {@link CompletableFuture}.
@@ -286,6 +288,7 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
     CompletableFuture<Boolean> thenPut(Put put);
 
     /**
+     * Specify a Delete to commit if the check succeeds.
      * @param delete data to delete if check succeeds
      * @return {@code true} if the new delete was executed, {@code false} otherwise. The return
      *         value will be wrapped by a {@link CompletableFuture}.
@@ -293,6 +296,7 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
     CompletableFuture<Boolean> thenDelete(Delete delete);
 
     /**
+     * Specify a RowMutations to commit if the check succeeds.
      * @param mutation mutations to perform if check succeeds
      * @return true if the new mutation was executed, false otherwise. The return value will be
      *         wrapped by a {@link CompletableFuture}.
@@ -308,16 +312,13 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
    * execute it. This is a fluent style API, the code is like:
    *
    * <pre>
-   * <code>
-   * table.checkAndMutate(row, filter).thenPut(put)
-   *     .thenAccept(succ -> {
-   *       if (succ) {
-   *         System.out.println("Check and put succeeded");
-   *       } else {
-   *         System.out.println("Check and put failed");
-   *       }
-   *     });
-   * </code>
+   * table.checkAndMutate(row, filter).thenPut(put).thenAccept(succ -&gt; {
+   *   if (succ) {
+   *     System.out.println("Check and put succeeded");
+   *   } else {
+   *     System.out.println("Check and put failed");
+   *   }
+   * });
    * </pre>
    *
    * @deprecated Since 3.0.0, will be removed in 4.0.0. For internal test use only, do not use it
@@ -335,11 +336,13 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
   interface CheckAndMutateWithFilterBuilder {
 
     /**
+     * Match a timerange.
      * @param timeRange time range to check.
      */
     CheckAndMutateWithFilterBuilder timeRange(TimeRange timeRange);
 
     /**
+     * Specify a Put to commit if the check succeeds.
      * @param put data to put if check succeeds
      * @return {@code true} if the new put was executed, {@code false} otherwise. The return value
      *         will be wrapped by a {@link CompletableFuture}.
@@ -347,6 +350,7 @@ interface CheckAndMutateWithFilterBuilder {
     CompletableFuture<Boolean> thenPut(Put put);
 
     /**
+     * Specify a Delete to commit if the check succeeds.
      * @param delete data to delete if check succeeds
      * @return {@code true} if the new delete was executed, {@code false} otherwise. The return
      *         value will be wrapped by a {@link CompletableFuture}.
@@ -354,6 +358,7 @@ interface CheckAndMutateWithFilterBuilder {
     CompletableFuture<Boolean> thenDelete(Delete delete);
 
     /**
+     * Specify a RowMutations to commit if the check succeeds.
      * @param mutation mutations to perform if check succeeds
      * @return true if the new mutation was executed, false otherwise. The return value will be
      *         wrapped by a {@link CompletableFuture}.
@@ -440,16 +445,14 @@ default ResultScanner getScanner(byte[] family, byte[] qualifier) {
    * <p>
    *
    * <pre>
-   * <code>
-   * table.scanAll(new Scan().withStartRow(row, false).setLimit(1)).thenAccept(results -> {
+   * table.scanAll(new Scan().withStartRow(row, false).setLimit(1)).thenAccept(results -&gt; {
    *   if (results.isEmpty()) {
-   *      System.out.println("No row after " + Bytes.toStringBinary(row));
+   *     System.out.println("No row after " + Bytes.toStringBinary(row));
    *   } else {
    *     System.out.println("The closest row after " + Bytes.toStringBinary(row) + " is "
-   *         + Bytes.toStringBinary(results.stream().findFirst().get().getRow()));
+   *       + Bytes.toStringBinary(results.stream().findFirst().get().getRow()));
    *   }
    * });
-   * </code>
    * </pre>
    * <p>
    * If your result set is very large, you should use other scan method to get a scanner or use
@@ -574,9 +577,7 @@ default <T> CompletableFuture<List<T>> batchAll(List<? extends Row> actions) {
    * one line lambda expression, like:
    *
    * <pre>
-   * <code>
-   * channel -> xxxService.newStub(channel)
-   * </code>
+   * channel -&gt; xxxService.newStub(channel)
    * </pre>
    *
    * @param stubMaker a delegation to the actual {@code newStub} call.
@@ -609,7 +610,7 @@ <S, R> CompletableFuture<R> coprocessorService(Function<RpcChannel, S> stubMaker
    *
    * <pre>
    * locateThenCall(byte[] row) {
-   *   locate(row).whenComplete((location, locateError) -> {
+   *   locate(row).whenComplete((location, locateError) -&gt; {
    *     if (locateError != null) {
    *       callback.onError(locateError);
    *       return;
@@ -621,7 +622,7 @@ <S, R> CompletableFuture<R> coprocessorService(Function<RpcChannel, S> stubMaker
    *     } else {
    *       locateThenCall(region.getEndKey());
    *     }
-   *     sendCall().whenComplete((resp, error) -> {
+   *     sendCall().whenComplete((resp, error) -&gt; {
    *       if (error != null) {
    *         callback.onRegionError(region, error);
    *       } else {
@@ -639,12 +640,14 @@ <S, R> CompletableFuture<R> coprocessorService(Function<RpcChannel, S> stubMaker
   interface CoprocessorCallback<R> {
 
     /**
+     * Indicate that the respose of a region is available
      * @param region the region that the response belongs to
      * @param resp   the response of the coprocessor call
      */
     void onRegionComplete(RegionInfo region, R resp);
 
     /**
+     * Indicate that the error for a region is available
      * @param region the region that the error belongs to
      * @param error  the response error of the coprocessor call
      */
@@ -675,6 +678,7 @@ interface CoprocessorCallback<R> {
   interface CoprocessorServiceBuilder<S, R> {
 
     /**
+     * Specify a start row
      * @param startKey start region selection with region containing this row, inclusive.
      */
     default CoprocessorServiceBuilder<S, R> fromRow(byte[] startKey) {
@@ -682,12 +686,14 @@ default CoprocessorServiceBuilder<S, R> fromRow(byte[] startKey) {
     }
 
     /**
+     * Specify a start row
      * @param startKey  start region selection with region containing this row
      * @param inclusive whether to include the startKey
      */
     CoprocessorServiceBuilder<S, R> fromRow(byte[] startKey, boolean inclusive);
 
     /**
+     * Specify a stop row
      * @param endKey select regions up to and including the region containing this row, exclusive.
      */
     default CoprocessorServiceBuilder<S, R> toRow(byte[] endKey) {
@@ -695,6 +701,7 @@ default CoprocessorServiceBuilder<S, R> toRow(byte[] endKey) {
     }
 
     /**
+     * Specify a stop row
      * @param endKey    select regions up to and including the region containing this row
      * @param inclusive whether to include the endKey
      */
@@ -716,9 +723,7 @@ default CoprocessorServiceBuilder<S, R> toRow(byte[] endKey) {
    * is only a one line lambda expression, like:
    *
    * <pre>
-   * <code>
-   * channel -> xxxService.newStub(channel)
-   * </code>
+   * channel -&gt; xxxService.newStub(channel)
    * </pre>
    *
    * @param stubMaker a delegation to the actual {@code newStub} call.
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSimpleSelector.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSimpleSelector.java
index 2e704c5bdc10..e990fa6d65ff 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSimpleSelector.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSimpleSelector.java
@@ -128,6 +128,7 @@ public String toString() {
    * Selector's internal state.
    * @param loc the location which causes exception.
    */
+  @Override
   public void onError(HRegionLocation loc) {
     ConcurrentNavigableMap<byte[], StaleLocationCacheEntry> tableCache = computeIfAbsent(staleCache,
       loc.getRegion().getTable(), () -> new ConcurrentSkipListMap<>(BYTES_COMPARATOR));
@@ -159,18 +160,19 @@ private int getRandomReplicaId() {
    * When it looks up a location, it will call this method to find a replica region to go. For a
    * normal case, > 99% of region locations from catalog/meta replica will be up to date. In extreme
    * cases such as region server crashes, it will depends on how fast replication catches up.
-   * @param tablename  table name it looks up
+   * @param tableName  table name it looks up
    * @param row        key it looks up.
    * @param locateType locateType, Only BEFORE and CURRENT will be passed in.
    * @return catalog replica id
    */
-  public int select(final TableName tablename, final byte[] row,
+  @Override
+  public int select(final TableName tableName, final byte[] row,
     final RegionLocateType locateType) {
     Preconditions.checkArgument(
       locateType == RegionLocateType.BEFORE || locateType == RegionLocateType.CURRENT,
       "Expected type BEFORE or CURRENT but got: %s", locateType);
 
-    ConcurrentNavigableMap<byte[], StaleLocationCacheEntry> tableCache = staleCache.get(tablename);
+    ConcurrentNavigableMap<byte[], StaleLocationCacheEntry> tableCache = staleCache.get(tableName);
 
     // If there is no entry in StaleCache, select a random replica id.
     if (tableCache == null) {
@@ -199,7 +201,7 @@ public int select(final TableName tablename, final byte[] row,
       (EnvironmentEdgeManager.currentTime() - entry.getValue().getTimestamp())
           >= STALE_CACHE_TIMEOUT_IN_MILLISECONDS
     ) {
-      LOG.debug("Entry for table {} with startKey {}, {} times out", tablename, entry.getKey(),
+      LOG.debug("Entry for table {} with startKey {}, {} times out", tableName, entry.getKey(),
         entry);
       tableCache.remove(entry.getKey());
       return getRandomReplicaId();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CheckAndMutate.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CheckAndMutate.java
index 56402fb42f88..b31a0b27242f 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CheckAndMutate.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CheckAndMutate.java
@@ -97,6 +97,7 @@ public Builder ifEquals(byte[] family, byte[] qualifier, byte[] value) {
     }
 
     /**
+     * Check for match
      * @param family    family to check
      * @param qualifier qualifier to check
      * @param compareOp comparison operator to use
@@ -113,6 +114,7 @@ public Builder ifMatches(byte[] family, byte[] qualifier, CompareOperator compar
     }
 
     /**
+     * Check for match
      * @param filter filter to check
      * @return the CheckAndMutate object
      */
@@ -122,6 +124,7 @@ public Builder ifMatches(Filter filter) {
     }
 
     /**
+     * Specify a timerange
      * @param timeRange time range to check
      * @return the CheckAndMutate object
      */
@@ -144,6 +147,7 @@ private void preCheck(Row action) {
     }
 
     /**
+     * Build the CheckAndMutate object
      * @param put data to put if check succeeds
      * @return a CheckAndMutate object
      */
@@ -157,6 +161,7 @@ public CheckAndMutate build(Put put) {
     }
 
     /**
+     * Build the CheckAndMutate object
      * @param delete data to delete if check succeeds
      * @return a CheckAndMutate object
      */
@@ -170,6 +175,7 @@ public CheckAndMutate build(Delete delete) {
     }
 
     /**
+     * Build the CheckAndMutate object with an Increment to commit if the check succeeds.
      * @param increment data to increment if check succeeds
      * @return a CheckAndMutate object
      */
@@ -183,6 +189,7 @@ public CheckAndMutate build(Increment increment) {
     }
 
     /**
+     * Build the CheckAndMutate object with an Append to commit if the check succeeds.
      * @param append data to append if check succeeds
      * @return a CheckAndMutate object
      */
@@ -196,6 +203,7 @@ public CheckAndMutate build(Append append) {
     }
 
     /**
+     * Build the CheckAndMutate object with a RowMutations to commit if the check succeeds.
      * @param mutations mutations to perform if check succeeds
      * @return a CheckAndMutate object
      */
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
index f5bedbe88d2e..02df5dab2b91 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
@@ -19,6 +19,7 @@
 
 import java.io.IOException;
 import java.lang.management.ManagementFactory;
+import java.util.List;
 import org.apache.hadoop.hbase.util.Addressing;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
@@ -26,6 +27,8 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+
 /**
  * The class that is able to determine some unique strings for the client, such as an IP address,
  * PID, and composite deterministic ID.
@@ -38,8 +41,8 @@ private ClientIdGenerator() {
   }
 
   /**
-   * @return a unique ID incorporating IP address, PID, TID and timer. Might be an overkill... Note
-   *         though that new UUID in java by default is just a random number.
+   * Returns a unique ID incorporating IP address, PID, TID and timer. Might be an overkill... Note
+   * though that new UUID in java by default is just a random number.
    */
   public static byte[] generateClientId() {
     byte[] selfBytes = getIpAddressBytes();
@@ -61,10 +64,10 @@ public static byte[] generateClientId() {
   /** Returns PID of the current process, if it can be extracted from JVM name, or null. */
   public static Long getPid() {
     String name = ManagementFactory.getRuntimeMXBean().getName();
-    String[] nameParts = name.split("@");
-    if (nameParts.length == 2) { // 12345@somewhere
+    List<String> nameParts = Splitter.on('@').splitToList(name);
+    if (nameParts.size() == 2) { // 12345@somewhere
       try {
-        return Long.parseLong(nameParts[0]);
+        return Long.parseLong(nameParts.iterator().next()); // first element
       } catch (NumberFormatException ex) {
         LOG.warn("Failed to get PID from [" + name + "]", ex);
       }
@@ -75,8 +78,8 @@ public static Long getPid() {
   }
 
   /**
-   * @return Some IPv4/IPv6 address available on the current machine that is up, not virtual and not
-   *         a loopback address. Empty array if none can be found or error occurred.
+   * Returns Some IPv4/IPv6 address available on the current machine that is up, not virtual and not
+   * a loopback address. Empty array if none can be found or error occurred.
    */
   public static byte[] getIpAddressBytes() {
     try {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptor.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptor.java
index b3d8e4fd6009..d73e67ee0fbf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptor.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptor.java
@@ -98,10 +98,7 @@ public interface ColumnFamilyDescriptor {
   /** Returns an unmodifiable map. */
   Map<String, String> getConfiguration();
 
-  /**
-   * @param key the key whose associated value is to be returned
-   * @return accessing the configuration value by key.
-   */
+  /** Returns accessing the configuration value by key. */
   String getConfigurationValue(String key);
 
   /** Returns replication factor set for this CF */
@@ -117,8 +114,8 @@ public interface ColumnFamilyDescriptor {
   String getEncryptionType();
 
   /**
-   * @return in-memory compaction policy if set for the cf. Returns null if no policy is set for for
-   *         this column family
+   * Returns in-memory compaction policy if set for the cf. Returns null if no policy is set for for
+   * this column family
    */
   MemoryCompactionPolicy getInMemoryCompaction();
 
@@ -163,32 +160,35 @@ public interface ColumnFamilyDescriptor {
   int getTimeToLive();
 
   /**
+   * Get a configuration value.
    * @param key The key.
    * @return A clone value. Null if no mapping for the key
    */
   Bytes getValue(Bytes key);
 
   /**
+   * Get a configuration value.
    * @param key The key.
    * @return A clone value. Null if no mapping for the key
    */
   String getValue(String key);
 
   /**
+   * Get a configuration value.
    * @param key The key.
    * @return A clone value. Null if no mapping for the key
    */
   byte[] getValue(byte[] key);
 
   /**
-   * It clone all bytes of all elements.
+   * Get all configuration values. It clone all bytes of all elements.
    * @return All values
    */
   Map<Bytes, Bytes> getValues();
 
   /**
-   * @return True if hfile DATA type blocks should be cached (You cannot disable caching of INDEX
-   *         and BLOOM type blocks).
+   * Returns True if hfile DATA type blocks should be cached (You cannot disable caching of INDEX
+   * and BLOOM type blocks).
    */
   boolean isBlockCacheEnabled();
 
@@ -202,8 +202,8 @@ public interface ColumnFamilyDescriptor {
   boolean isCacheIndexesOnWrite();
 
   /**
-   * @return Whether KV tags should be compressed along with DataBlockEncoding. When no
-   *         DataBlockEncoding is been used, this is having no effect.
+   * Returns Whether KV tags should be compressed along with DataBlockEncoding. When no
+   * DataBlockEncoding is been used, this is having no effect.
    */
   boolean isCompressTags();
 
@@ -211,8 +211,8 @@ public interface ColumnFamilyDescriptor {
   boolean isEvictBlocksOnClose();
 
   /**
-   * @return True if we are to favor keeping all values for this column family in the HRegionServer
-   *         cache.
+   * Returns True if we are to favor keeping all values for this column family in the HRegionServer
+   * cache.
    */
   boolean isInMemory();
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java
index 80178027b6f2..cf4de2edfecf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java
@@ -42,9 +42,6 @@
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.ColumnFamilySchema;
 
-/**
- * @since 2.0.0
- */
 @InterfaceAudience.Public
 public class ColumnFamilyDescriptorBuilder {
   // For future backward compatibility
@@ -330,6 +327,7 @@ public static Unit getUnit(String key) {
   }
 
   /**
+   * Check if the column family name is legal.
    * @param b Family name.
    * @return <code>b</code>
    * @throws IllegalArgumentException If not null and not a legitimate family name: i.e. 'printable'
@@ -398,6 +396,7 @@ private ColumnFamilyDescriptorBuilder(final ColumnFamilyDescriptor desc) {
   }
 
   /**
+   * Serialize the table descriptor to a byte array.
    * @param desc The table descriptor to serialize
    * @return This instance serialized with pb with pb magic prefix
    */
@@ -690,11 +689,6 @@ public Map<Bytes, Bytes> getValues() {
       return Collections.unmodifiableMap(values);
     }
 
-    /**
-     * @param key   The key.
-     * @param value The value.
-     * @return this (for chained invocation)
-     */
     public ModifyableColumnFamilyDescriptor setValue(byte[] key, byte[] value) {
       return setValue(toBytesOrNull(key, Function.identity()),
         toBytesOrNull(value, Function.identity()));
@@ -708,11 +702,6 @@ private ModifyableColumnFamilyDescriptor setValue(Bytes key, String value) {
       return setValue(key, toBytesOrNull(value, Bytes::toBytes));
     }
 
-    /**
-     * @param key   The key.
-     * @param value The value.
-     * @return this (for chained invocation)
-     */
     private ModifyableColumnFamilyDescriptor setValue(Bytes key, Bytes value) {
       if (value == null || value.getLength() == 0) {
         values.remove(key);
@@ -749,6 +738,7 @@ public int getMaxVersions() {
     }
 
     /**
+     * Set the maximum number of versions to retain.
      * @param maxVersions maximum number of versions
      * @return this (for chained invocation)
      */
@@ -768,7 +758,7 @@ public ModifyableColumnFamilyDescriptor setMaxVersions(int maxVersions) {
     }
 
     /**
-     * Set minimum and maximum versions to keep
+     * Set minimum and maximum versions to keep.
      * @param minVersions minimal number of versions
      * @param maxVersions maximum number of versions
      * @return this (for chained invocation)
@@ -795,10 +785,6 @@ public int getBlocksize() {
       return getStringOrDefault(BLOCKSIZE_BYTES, Integer::valueOf, DEFAULT_BLOCKSIZE);
     }
 
-    /**
-     * @param s Blocksize to use when writing out storefiles/hfiles on this column family.
-     * @return this (for chained invocation)
-     */
     public ModifyableColumnFamilyDescriptor setBlocksize(int s) {
       return setValue(BLOCKSIZE_BYTES, Integer.toString(s));
     }
@@ -901,6 +887,7 @@ public boolean isInMemory() {
     }
 
     /**
+     * Set the inMemory flag
      * @param inMemory True if we are to favor keeping all values for this column family in the
      *                 HRegionServer cache
      * @return this (for chained invocation)
@@ -915,10 +902,6 @@ public MemoryCompactionPolicy getInMemoryCompaction() {
         n -> MemoryCompactionPolicy.valueOf(n.toUpperCase()), null);
     }
 
-    /**
-     * @param inMemoryCompaction the prefered in-memory compaction policy for this column family
-     * @return this (for chained invocation)
-     */
     public ModifyableColumnFamilyDescriptor
       setInMemoryCompaction(MemoryCompactionPolicy inMemoryCompaction) {
       return setValue(IN_MEMORY_COMPACTION_BYTES, inMemoryCompaction.name());
@@ -930,10 +913,6 @@ public KeepDeletedCells getKeepDeletedCells() {
         DEFAULT_KEEP_DELETED);
     }
 
-    /**
-     * @param keepDeletedCells True if deleted rows should not be collected immediately.
-     * @return this (for chained invocation)
-     */
     public ModifyableColumnFamilyDescriptor setKeepDeletedCells(KeepDeletedCells keepDeletedCells) {
       return setValue(KEEP_DELETED_CELLS_BYTES, keepDeletedCells.name());
     }
@@ -959,6 +938,7 @@ public int getTimeToLive() {
     }
 
     /**
+     * Set the time to live
      * @param timeToLive Time-to-live of cell contents, in seconds.
      * @return this (for chained invocation)
      */
@@ -967,9 +947,10 @@ public ModifyableColumnFamilyDescriptor setTimeToLive(int timeToLive) {
     }
 
     /**
+     * Set the time to live
      * @param timeToLive Time-to-live of cell contents, in seconds.
      * @return this (for chained invocation)
-     * @throws org.apache.hadoop.hbase.exceptions.HBaseException
+     * @throws org.apache.hadoop.hbase.exceptions.HBaseException exception
      */
     public ModifyableColumnFamilyDescriptor setTimeToLive(String timeToLive) throws HBaseException {
       return setTimeToLive(Integer.parseInt(PrettyPrinter.valueOf(timeToLive, Unit.TIME_INTERVAL)));
@@ -981,6 +962,7 @@ public int getMinVersions() {
     }
 
     /**
+     * Set minimum versions to retain.
      * @param minVersions The minimum number of versions to keep. (used when timeToLive is set)
      * @return this (for chained invocation)
      */
@@ -1010,6 +992,7 @@ public boolean isBlockCacheEnabled() {
     }
 
     /**
+     * Set the blockCacheEnabled flag
      * @param blockCacheEnabled True if hfile DATA type blocks should be cached (We always cache
      *                          INDEX and BLOOM blocks; you cannot turn this off).
      * @return this (for chained invocation)
@@ -1034,10 +1017,6 @@ public int getScope() {
         DEFAULT_REPLICATION_SCOPE);
     }
 
-    /**
-     * @param scope the scope tag
-     * @return this (for chained invocation)
-     */
     public ModifyableColumnFamilyDescriptor setScope(int scope) {
       return setValue(REPLICATION_SCOPE_BYTES, Integer.toString(scope));
     }
@@ -1049,6 +1028,7 @@ public boolean isCacheDataOnWrite() {
     }
 
     /**
+     * Set the setCacheDataOnWrite flag
      * @param value true if we should cache data blocks on write
      * @return this (for chained invocation)
      */
@@ -1063,6 +1043,7 @@ public boolean isCacheIndexesOnWrite() {
     }
 
     /**
+     * Set the setCacheIndexesOnWrite flag
      * @param value true if we should cache index blocks on write
      * @return this (for chained invocation)
      */
@@ -1077,6 +1058,7 @@ public boolean isCacheBloomsOnWrite() {
     }
 
     /**
+     * Set the setCacheBloomsOnWrite flag.
      * @param value true if we should cache bloomfilter blocks on write
      * @return this (for chained invocation)
      */
@@ -1091,6 +1073,7 @@ public boolean isEvictBlocksOnClose() {
     }
 
     /**
+     * Set the setEvictBlocksOnClose flag.
      * @param value true if we should evict cached blocks from the blockcache on close
      * @return this (for chained invocation)
      */
@@ -1105,6 +1088,7 @@ public boolean isPrefetchBlocksOnOpen() {
     }
 
     /**
+     * Set the setPrefetchBlocksOnOpen flag
      * @param value true if we should prefetch blocks into the blockcache on open
      * @return this (for chained invocation)
      */
@@ -1232,19 +1216,17 @@ public int compareTo(ModifyableColumnFamilyDescriptor other) {
       return COMPARATOR.compare(this, other);
     }
 
-    /**
-     * @return This instance serialized with pb with pb magic prefix
-     * @see #parseFrom(byte[])
-     */
+    /** Returns This instance serialized with pb with pb magic prefix */
     private byte[] toByteArray() {
       return ProtobufUtil.prependPBMagic(ProtobufUtil.toColumnFamilySchema(this).toByteArray());
     }
 
     /**
+     * Parse the serialized representation of a {@link ModifyableColumnFamilyDescriptor}
      * @param bytes A pb serialized {@link ModifyableColumnFamilyDescriptor} instance with pb magic
      *              prefix
      * @return An instance of {@link ModifyableColumnFamilyDescriptor} made from <code>bytes</code>
-     *         n * @see #toByteArray()
+     * @see #toByteArray()
      */
     private static ColumnFamilyDescriptor parseFrom(final byte[] bytes)
       throws DeserializationException {
@@ -1290,8 +1272,8 @@ public ModifyableColumnFamilyDescriptor setConfiguration(String key, String valu
     }
 
     /**
-     * Remove a configuration setting represented by the key from the {@link #configuration} map. n
-     * * @return this (for chained invocation)
+     * Remove a configuration setting represented by the key from the {@link #configuration} map.
+     * @return this (for chained invocation)
      */
     public ModifyableColumnFamilyDescriptor removeConfiguration(final String key) {
       return setConfiguration(key, null);
@@ -1303,8 +1285,8 @@ public String getEncryptionType() {
     }
 
     /**
-     * Set the encryption algorithm for use with this family n * @return this (for chained
-     * invocation)
+     * Set the encryption algorithm for use with this family
+     * @return this (for chained invocation)
      */
     public ModifyableColumnFamilyDescriptor setEncryptionType(String algorithm) {
       return setValue(ENCRYPTION_BYTES, algorithm);
@@ -1316,7 +1298,8 @@ public byte[] getEncryptionKey() {
     }
 
     /**
-     * Set the raw crypto key attribute for the family n * @return this (for chained invocation)
+     * Set the raw crypto key attribute for the family
+     * @return this (for chained invocation)
      */
     public ModifyableColumnFamilyDescriptor setEncryptionKey(byte[] keyBytes) {
       return setValue(ENCRYPTION_KEY_BYTES, new Bytes(keyBytes));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CompactType.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CompactType.java
index 225bb072db70..412fd76d9ecf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CompactType.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/CompactType.java
@@ -26,9 +26,7 @@
 @InterfaceAudience.Public
 public enum CompactType {
 
-  NORMAL(0),
-  MOB(1);
+  NORMAL,
+  MOB
 
-  CompactType(int value) {
-  }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Delete.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Delete.java
index 755c0ca0b8c0..545e8c38c4b0 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Delete.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Delete.java
@@ -111,8 +111,6 @@ public Delete(final byte[] row, final int rowOffset, final int rowLength) {
    * <p>
    * This timestamp is ONLY used for a delete row operation. If specifying families or columns, you
    * must specify each timestamp individually.
-   * @param row We make a local copy of this passed in row. nn * @param timestamp maximum version
-   *            timestamp (only for delete row)
    */
   public Delete(final byte[] row, final int rowOffset, final int rowLength, long timestamp) {
     checkRow(row, rowOffset, rowLength);
@@ -121,6 +119,7 @@ public Delete(final byte[] row, final int rowOffset, final int rowLength, long t
   }
 
   /**
+   * Create a Delete operation using another Delete as template.
    * @param deleteToCopy delete to copy
    */
   public Delete(final Delete deleteToCopy) {
@@ -144,6 +143,7 @@ public Delete(byte[] row, long ts, NavigableMap<byte[], List<Cell>> familyMap) {
    * @param cell An existing cell of type "delete".
    * @return this for invocation chaining n
    */
+  @Override
   public Delete add(Cell cell) throws IOException {
     super.add(cell);
     return this;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Get.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Get.java
index 17975ff631de..f4e06101255d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Get.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Get.java
@@ -445,7 +445,7 @@ public boolean equals(Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null || getClass() != obj.getClass()) {
+    if (!(obj instanceof Row)) {
       return false;
     }
     Row other = (Row) obj;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Increment.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Increment.java
index dea15cac8d50..e4b177e3bca8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Increment.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Increment.java
@@ -96,6 +96,7 @@ public Increment(byte[] row, long ts, NavigableMap<byte[], List<Cell>> familyMap
    * Add the specified KeyValue to this operation.
    * @param cell individual Cell n * @throws java.io.IOException e
    */
+  @Override
   public Increment add(Cell cell) throws IOException {
     super.add(cell);
     return this;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/IsolationLevel.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/IsolationLevel.java
index 7804e48de9f0..3f94fc30f9c7 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/IsolationLevel.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/IsolationLevel.java
@@ -29,11 +29,8 @@
 @InterfaceAudience.Public
 public enum IsolationLevel {
 
-  READ_COMMITTED(1),
-  READ_UNCOMMITTED(2);
-
-  IsolationLevel(int value) {
-  }
+  READ_COMMITTED,
+  READ_UNCOMMITTED;
 
   public byte[] toBytes() {
     return new byte[] { toByte() };
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/LogQueryFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/LogQueryFilter.java
index b2d217da3de0..61137076a128 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/LogQueryFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/LogQueryFilter.java
@@ -112,13 +112,10 @@ public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
-
-    if (o == null || getClass() != o.getClass()) {
+    if (!(o instanceof LogQueryFilter)) {
       return false;
     }
-
     LogQueryFilter that = (LogQueryFilter) o;
-
     return new EqualsBuilder().append(limit, that.limit).append(regionName, that.regionName)
       .append(clientAddress, that.clientAddress).append(tableName, that.tableName)
       .append(userName, that.userName).append(type, that.type)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterCoprocessorRpcChannelImpl.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterCoprocessorRpcChannelImpl.java
index 4be0362be85d..f36b3e162187 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterCoprocessorRpcChannelImpl.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterCoprocessorRpcChannelImpl.java
@@ -78,11 +78,11 @@ public void callMethod(MethodDescriptor method, RpcController controller, Messag
     Message responsePrototype, RpcCallback<Message> done) {
     addListener(
       callerBuilder.action((c, s) -> rpcCall(method, request, responsePrototype, c, s)).call(),
-      ((r, e) -> {
+      (r, e) -> {
         if (e != null) {
           ((ClientCoprocessorRpcController) controller).setFailed(e);
         }
         done.run(r);
-      }));
+      });
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterRegistry.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterRegistry.java
index a031d3530971..28ac5bb45282 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterRegistry.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MasterRegistry.java
@@ -34,6 +34,7 @@
 import org.apache.yetus.audience.InterfaceAudience;
 
 import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
 import org.apache.hbase.thirdparty.com.google.common.base.Strings;
 import org.apache.hbase.thirdparty.com.google.common.net.HostAndPort;
 
@@ -78,7 +79,8 @@ public class MasterRegistry extends AbstractRpcBasedConnectionRegistry {
   public static Set<ServerName> parseMasterAddrs(Configuration conf) throws UnknownHostException {
     Set<ServerName> masterAddrs = new HashSet<>();
     String configuredMasters = getMasterAddr(conf);
-    for (String masterAddr : configuredMasters.split(MASTER_ADDRS_CONF_SEPARATOR)) {
+    for (String masterAddr : Splitter.onPattern(MASTER_ADDRS_CONF_SEPARATOR)
+      .split(configuredMasters)) {
       HostAndPort masterHostPort =
         HostAndPort.fromString(masterAddr.trim()).withDefaultPort(HConstants.DEFAULT_MASTER_PORT);
       masterAddrs.add(ServerName.valueOf(masterHostPort.toString(), ServerName.NON_STARTCODE));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java
index b768b76fdb65..341341b4336e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java
@@ -53,11 +53,7 @@ public int size() {
     return size;
   }
 
-  /**
-   * Add the pair to the container, grouped by the regionName n * @param originalIndex the original
-   * index of the Action (request).
-   * @param resOrEx the result or error; will be empty for successful Put and Delete actions.
-   */
+  /** Add the pair to the container, grouped by the regionName. */
   public void add(byte[] regionName, int originalIndex, Object resOrEx) {
     getResult(regionName).addResult(originalIndex, resOrEx);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MutableRegionInfo.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MutableRegionInfo.java
index 7627f8dc0e5a..fbb76ea4f65d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MutableRegionInfo.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/MutableRegionInfo.java
@@ -230,6 +230,7 @@ public boolean isSplit() {
   }
 
   /**
+   * Change the split status flag.
    * @param split set split status n
    */
   public MutableRegionInfo setSplit(boolean split) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Mutation.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Mutation.java
index 3f82e4110eb2..df9e92f74dcd 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Mutation.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Mutation.java
@@ -156,7 +156,7 @@ List<Cell> getCellList(byte[] family) {
     return list;
   }
 
-  /*
+  /**
    * Create a KeyValue with this objects row key and the Put identifier.
    * @return a KeyValue with this objects row key and the Put identifier.
    */
@@ -165,8 +165,7 @@ KeyValue createPutKeyValue(byte[] family, byte[] qualifier, long ts, byte[] valu
   }
 
   /**
-   * Create a KeyValue with this objects row key and the Put identifier. nnnn * @param tags -
-   * Specify the Tags as an Array
+   * Create a KeyValue with this objects row key and the Put identifier.
    * @return a KeyValue with this objects row key and the Put identifier.
    */
   KeyValue createPutKeyValue(byte[] family, byte[] qualifier, long ts, byte[] value, Tag[] tags) {
@@ -174,7 +173,7 @@ KeyValue createPutKeyValue(byte[] family, byte[] qualifier, long ts, byte[] valu
     return kvWithTag;
   }
 
-  /*
+  /**
    * Create a KeyValue with this objects row key and the Put identifier.
    * @return a KeyValue with this objects row key and the Put identifier.
    */
@@ -187,7 +186,7 @@ KeyValue createPutKeyValue(byte[] family, ByteBuffer qualifier, long ts, ByteBuf
 
   /**
    * Compile the column family (i.e. schema) information into a Map. Useful for parsing and
-   * aggregation by debugging, logging, and administration tools. n
+   * aggregation by debugging, logging, and administration tools.
    */
   @Override
   public Map<String, Object> getFingerprint() {
@@ -261,7 +260,7 @@ private static Map<String, Object> cellToStringMap(Cell c) {
     if (tags != null) {
       List<String> tagsString = new ArrayList<>(tags.size());
       for (Tag t : tags) {
-        tagsString.add((t.getType()) + ":" + Bytes.toStringBinary(Tag.cloneValue(t)));
+        tagsString.add(t.getType() + ":" + Bytes.toStringBinary(Tag.cloneValue(t)));
       }
       stringMap.put("tag", tagsString);
     }
@@ -445,6 +444,7 @@ public byte[] getACL() {
   }
 
   /**
+   * Set the ACL for this operation.
    * @param user  User short name
    * @param perms Permissions for the user
    */
@@ -455,6 +455,7 @@ public Mutation setACL(String user, Permission perms) {
   }
 
   /**
+   * Set the ACL for this operation.
    * @param perms A map of permissions for a user or users
    */
   public Mutation setACL(Map<String, Permission> perms) {
@@ -596,11 +597,9 @@ public List<Cell> get(byte[] family, byte[] qualifier) {
     return filteredList;
   }
 
-  /*
+  /**
    * Private method to determine if this object's familyMap contains the given value assigned to the
-   * given family, qualifier and timestamp respecting the 2 boolean arguments nnnnnn * @return
-   * returns true if the given family, qualifier timestamp and value already has an existing
-   * KeyValue object in the family map.
+   * given family, qualifier and timestamp, respecting the 2 boolean arguments.
    */
   protected boolean has(byte[] family, byte[] qualifier, long ts, byte[] value, boolean ignoreTS,
     boolean ignoreValue) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Put.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Put.java
index bcc1bda9ef02..5e821f075461 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Put.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Put.java
@@ -203,6 +203,7 @@ public Put addColumn(byte[] family, ByteBuffer qualifier, long ts, ByteBuffer va
    * immutable and its backing array will not be modified for the duration of this Put.
    * @param cell individual cell n * @throws java.io.IOException e
    */
+  @Override
   public Put add(Cell cell) throws IOException {
     super.add(cell);
     return this;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Query.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Query.java
index 750993c1a8a2..cf892ae0d74b 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Query.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Query.java
@@ -88,6 +88,7 @@ public byte[] getACL() {
   }
 
   /**
+   * Set the ACL for the operation.
    * @param user  User short name
    * @param perms Permissions for the user
    */
@@ -98,6 +99,7 @@ public Query setACL(String user, Permission perms) {
   }
 
   /**
+   * Set the ACL for the operation.
    * @param perms A map of permissions for a user or users
    */
   public Query setACL(Map<String, Permission> perms) {
@@ -159,9 +161,8 @@ public Query setIsolationLevel(IsolationLevel level) {
   }
 
   /**
-   * @return The isolation level of this query. If no isolation level was set for this query object,
-   *         then it returns READ_COMMITTED.
-   * @return The IsolationLevel for this query
+   * Returns The isolation level of this query. If no isolation level was set for this query object,
+   * then it returns READ_COMMITTED.
    */
   public IsolationLevel getIsolationLevel() {
     byte[] attr = getAttribute(ISOLATION_LEVEL);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
index 3ec2c741293e..4d614907326e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
@@ -502,11 +502,6 @@ private <PREQ, PRESP> CompletableFuture<Void> procedureCall(
     return future;
   }
 
-  @FunctionalInterface
-  private interface TableOperator {
-    CompletableFuture<Void> operate(TableName table);
-  }
-
   @Override
   public CompletableFuture<Boolean> tableExists(TableName tableName) {
     if (TableName.isMetaTableName(tableName)) {
@@ -1559,11 +1554,13 @@ public CompletableFuture<Void> assign(byte[] regionName) {
         future.completeExceptionally(err);
         return;
       }
-      addListener(this.<Void> newMasterCaller().priority(regionInfo.getTable())
-        .action(((controller, stub) -> this.<AssignRegionRequest, AssignRegionResponse, Void> call(
-          controller, stub, RequestConverter.buildAssignRegionRequest(regionInfo.getRegionName()),
-          (s, c, req, done) -> s.assignRegion(c, req, done), resp -> null)))
-        .call(), (ret, err2) -> {
+      addListener(
+        this.<Void> newMasterCaller().priority(regionInfo.getTable())
+          .action((controller, stub) -> this.<AssignRegionRequest, AssignRegionResponse, Void> call(
+            controller, stub, RequestConverter.buildAssignRegionRequest(regionInfo.getRegionName()),
+            (s, c, req, done) -> s.assignRegion(c, req, done), resp -> null))
+          .call(),
+        (ret, err2) -> {
           if (err2 != null) {
             future.completeExceptionally(err2);
           } else {
@@ -1584,10 +1581,10 @@ public CompletableFuture<Void> unassign(byte[] regionName) {
       }
       addListener(
         this.<Void> newMasterCaller().priority(regionInfo.getTable())
-          .action(((controller, stub) -> this.<UnassignRegionRequest, UnassignRegionResponse,
+          .action((controller, stub) -> this.<UnassignRegionRequest, UnassignRegionResponse,
             Void> call(controller, stub,
               RequestConverter.buildUnassignRegionRequest(regionInfo.getRegionName()),
-              (s, c, req, done) -> s.unassignRegion(c, req, done), resp -> null)))
+              (s, c, req, done) -> s.unassignRegion(c, req, done), resp -> null))
           .call(),
         (ret, err2) -> {
           if (err2 != null) {
@@ -1608,14 +1605,11 @@ public CompletableFuture<Void> offline(byte[] regionName) {
         future.completeExceptionally(err);
         return;
       }
-      addListener(
-        this.<Void> newMasterCaller().priority(regionInfo.getTable())
-          .action(((controller, stub) -> this.<OfflineRegionRequest, OfflineRegionResponse,
-            Void> call(controller, stub,
-              RequestConverter.buildOfflineRegionRequest(regionInfo.getRegionName()),
-              (s, c, req, done) -> s.offlineRegion(c, req, done), resp -> null)))
-          .call(),
-        (ret, err2) -> {
+      addListener(this.<Void> newMasterCaller().priority(regionInfo.getTable())
+        .action((controller, stub) -> this.<OfflineRegionRequest, OfflineRegionResponse, Void> call(
+          controller, stub, RequestConverter.buildOfflineRegionRequest(regionInfo.getRegionName()),
+          (s, c, req, done) -> s.offlineRegion(c, req, done), resp -> null))
+        .call(), (ret, err2) -> {
           if (err2 != null) {
             future.completeExceptionally(err2);
           } else {
@@ -2236,7 +2230,7 @@ private CompletableFuture<Void> internalDeleteSnapshots(Pattern tableNamePattern
       listSnapshotsFuture = getCompletedSnapshots(tableNamePattern, snapshotNamePattern);
     }
     CompletableFuture<Void> future = new CompletableFuture<>();
-    addListener(listSnapshotsFuture, ((snapshotDescriptions, err) -> {
+    addListener(listSnapshotsFuture, (snapshotDescriptions, err) -> {
       if (err != null) {
         future.completeExceptionally(err);
         return;
@@ -2253,7 +2247,7 @@ private CompletableFuture<Void> internalDeleteSnapshots(Pattern tableNamePattern
             future.complete(v);
           }
         });
-    }));
+    });
     return future;
   }
 
@@ -4010,10 +4004,9 @@ public CompletableFuture<Void> moveServersToRSGroup(Set<Address> servers, String
   @Override
   public CompletableFuture<Void> addRSGroup(String groupName) {
     return this.<Void> newMasterCaller()
-      .action(
-        ((controller, stub) -> this.<AddRSGroupRequest, AddRSGroupResponse, Void> call(controller,
-          stub, AddRSGroupRequest.newBuilder().setRSGroupName(groupName).build(),
-          (s, c, req, done) -> s.addRSGroup(c, req, done), resp -> null)))
+      .action((controller, stub) -> this.<AddRSGroupRequest, AddRSGroupResponse, Void> call(
+        controller, stub, AddRSGroupRequest.newBuilder().setRSGroupName(groupName).build(),
+        (s, c, req, done) -> s.addRSGroup(c, req, done), resp -> null))
       .call();
   }
 
@@ -4081,9 +4074,9 @@ private CompletableFuture<List<LogEntry>> getSlowLogResponseFromServer(ServerNam
 
   private CompletableFuture<Boolean> clearSlowLogsResponses(final ServerName serverName) {
     return this.<Boolean> newAdminCaller()
-      .action(((controller, stub) -> this.adminCall(controller, stub,
+      .action((controller, stub) -> this.adminCall(controller, stub,
         RequestConverter.buildClearSlowLogResponseRequest(),
-        AdminService.Interface::clearSlowLogsResponses, ProtobufUtil::toClearSlowLogPayload)))
+        AdminService.Interface::clearSlowLogsResponses, ProtobufUtil::toClearSlowLogPayload))
       .serverName(serverName).call();
   }
 
@@ -4124,15 +4117,14 @@ Pair<List<String>, List<TableName>>> call(controller, stub,
   @Override
   public CompletableFuture<RSGroupInfo> getRSGroup(Address hostPort) {
     return this.<RSGroupInfo> newMasterCaller()
-      .action(
-        ((controller, stub) -> this.<GetRSGroupInfoOfServerRequest, GetRSGroupInfoOfServerResponse,
-          RSGroupInfo> call(controller, stub, GetRSGroupInfoOfServerRequest.newBuilder()
+      .action((controller, stub) -> this.<GetRSGroupInfoOfServerRequest,
+        GetRSGroupInfoOfServerResponse, RSGroupInfo> call(controller, stub,
+          GetRSGroupInfoOfServerRequest.newBuilder()
             .setServer(HBaseProtos.ServerName.newBuilder().setHostName(hostPort.getHostname())
               .setPort(hostPort.getPort()).build())
-            .build(), (s, c, req, done) -> s.getRSGroupInfoOfServer(c, req, done),
-            resp -> resp.hasRSGroupInfo()
-              ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo())
-              : null)))
+            .build(),
+          (s, c, req, done) -> s.getRSGroupInfoOfServer(c, req, done),
+          resp -> resp.hasRSGroupInfo() ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo()) : null))
       .call();
   }
 
@@ -4160,7 +4152,7 @@ public CompletableFuture<Void> setRSGroup(Set<TableName> tables, String groupNam
         }
       });
     }
-    addListener(listTableDescriptors(new ArrayList<>(tables)), ((tableDescriptions, err) -> {
+    addListener(listTableDescriptors(new ArrayList<>(tables)), (tableDescriptions, err) -> {
       if (err != null) {
         future.completeExceptionally(err);
         return;
@@ -4184,40 +4176,40 @@ public CompletableFuture<Void> setRSGroup(Set<TableName> tables, String groupNam
             future.complete(v);
           }
         });
-    }));
+    });
     return future;
   }
 
   @Override
   public CompletableFuture<RSGroupInfo> getRSGroup(TableName table) {
     return this.<RSGroupInfo> newMasterCaller()
-      .action(((controller, stub) -> this.<GetRSGroupInfoOfTableRequest,
+      .action((controller, stub) -> this.<GetRSGroupInfoOfTableRequest,
         GetRSGroupInfoOfTableResponse, RSGroupInfo> call(controller, stub,
           GetRSGroupInfoOfTableRequest.newBuilder()
             .setTableName(ProtobufUtil.toProtoTableName(table)).build(),
           (s, c, req, done) -> s.getRSGroupInfoOfTable(c, req, done),
-          resp -> resp.hasRSGroupInfo() ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo()) : null)))
+          resp -> resp.hasRSGroupInfo() ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo()) : null))
       .call();
   }
 
   @Override
   public CompletableFuture<RSGroupInfo> getRSGroup(String groupName) {
     return this.<RSGroupInfo> newMasterCaller()
-      .action(((controller, stub) -> this.<GetRSGroupInfoRequest, GetRSGroupInfoResponse,
+      .action((controller, stub) -> this.<GetRSGroupInfoRequest, GetRSGroupInfoResponse,
         RSGroupInfo> call(controller, stub,
           GetRSGroupInfoRequest.newBuilder().setRSGroupName(groupName).build(),
           (s, c, req, done) -> s.getRSGroupInfo(c, req, done),
-          resp -> resp.hasRSGroupInfo() ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo()) : null)))
+          resp -> resp.hasRSGroupInfo() ? ProtobufUtil.toGroupInfo(resp.getRSGroupInfo()) : null))
       .call();
   }
 
   @Override
   public CompletableFuture<Void> renameRSGroup(String oldName, String newName) {
     return this.<Void> newMasterCaller()
-      .action(((controller, stub) -> this.<RenameRSGroupRequest, RenameRSGroupResponse, Void> call(
+      .action((controller, stub) -> this.<RenameRSGroupRequest, RenameRSGroupResponse, Void> call(
         controller, stub, RenameRSGroupRequest.newBuilder().setOldRsgroupName(oldName)
           .setNewRsgroupName(newName).build(),
-        (s, c, req, done) -> s.renameRSGroup(c, req, done), resp -> null)))
+        (s, c, req, done) -> s.renameRSGroup(c, req, done), resp -> null))
       .call();
   }
 
@@ -4231,9 +4223,9 @@ public CompletableFuture<Void> updateRSGroupConfig(String groupName,
         NameStringPair.newBuilder().setName(e.getKey()).setValue(e.getValue()).build()));
     }
     return this.<Void> newMasterCaller()
-      .action(((controller, stub) -> this.<UpdateRSGroupConfigRequest, UpdateRSGroupConfigResponse,
+      .action((controller, stub) -> this.<UpdateRSGroupConfigRequest, UpdateRSGroupConfigResponse,
         Void> call(controller, stub, request.build(),
-          (s, c, req, done) -> s.updateRSGroupConfig(c, req, done), resp -> null)))
+          (s, c, req, done) -> s.updateRSGroupConfig(c, req, done), resp -> null))
       .call();
   }
 
@@ -4287,9 +4279,9 @@ public CompletableFuture<List<LogEntry>> getLogEntries(Set<ServerName> serverNam
   public CompletableFuture<Void> flushMasterStore() {
     FlushMasterStoreRequest.Builder request = FlushMasterStoreRequest.newBuilder();
     return this.<Void> newMasterCaller()
-      .action(((controller, stub) -> this.<FlushMasterStoreRequest, FlushMasterStoreResponse,
+      .action((controller, stub) -> this.<FlushMasterStoreRequest, FlushMasterStoreResponse,
         Void> call(controller, stub, request.build(),
-          (s, c, req, done) -> s.flushMasterStore(c, req, done), resp -> null)))
+          (s, c, req, done) -> s.flushMasterStore(c, req, done), resp -> null))
       .call();
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncTableImpl.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncTableImpl.java
index af0b20908031..ff75c0725ce5 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncTableImpl.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncTableImpl.java
@@ -776,7 +776,7 @@ private boolean locateFinished(RegionInfo region, byte[] endKey, boolean endKeyI
       int c = Bytes.compareTo(endKey, region.getEndKey());
       // 1. if the region contains endKey
       // 2. endKey is equal to the region's endKey and we do not want to include endKey.
-      return c < 0 || c == 0 && !endKeyInclusive;
+      return c < 0 || (c == 0 && !endKeyInclusive);
     }
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionCoprocessorServiceExec.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionCoprocessorServiceExec.java
index 4bf726079463..de3bc9a90d4a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionCoprocessorServiceExec.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionCoprocessorServiceExec.java
@@ -92,7 +92,7 @@ public boolean equals(Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null || getClass() != obj.getClass()) {
+    if (!(obj instanceof RegionCoprocessorServiceExec)) {
       return false;
     }
     return compareTo((RegionCoprocessorServiceExec) obj) == 0;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionInfo.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionInfo.java
index 32c7da05887c..d1384d71469a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionInfo.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionInfo.java
@@ -160,7 +160,7 @@ public interface RegionInfo extends Comparable<RegionInfo> {
   long getRegionId();
 
   /**
-   * @return the regionName as an array of bytes.
+   * Returns the regionName as an array of bytes.
    * @see #getRegionNameAsString()
    */
   byte[] getRegionName();
@@ -190,7 +190,7 @@ public interface RegionInfo extends Comparable<RegionInfo> {
   boolean isSplit();
 
   /**
-   * @return True if this region is offline.
+   * Returns True if this region is offline.
    * @deprecated since 3.0.0 and will be removed in 4.0.0
    * @see <a href="https://issues.apache.org/jira/browse/HBASE-25210">HBASE-25210</a>
    */
@@ -198,7 +198,7 @@ public interface RegionInfo extends Comparable<RegionInfo> {
   boolean isOffline();
 
   /**
-   * @return True if this is a split parent region.
+   * Returns True if this is a split parent region.
    * @deprecated since 3.0.0 and will be removed in 4.0.0, Use {@link #isSplit()} instead.
    * @see <a href="https://issues.apache.org/jira/browse/HBASE-25210">HBASE-25210</a>
    */
@@ -209,9 +209,9 @@ public interface RegionInfo extends Comparable<RegionInfo> {
   boolean isMetaRegion();
 
   /**
-   * @return true if the given inclusive range of rows is fully contained by this region. For
-   *         example, if the region is foo,a,g and this is passed ["b","c"] or ["a","c"] it will
-   *         return true, but if this is passed ["b","z"] it will return false.
+   * Returns true if the given inclusive range of rows is fully contained by this region. For
+   * example, if the region is foo,a,g and this is passed ["b","c"] or ["a","c"] it will return
+   * true, but if this is passed ["b","z"] it will return false.
    * @throws IllegalArgumentException if the range passed is invalid (ie. end &lt; start)
    */
   boolean containsRange(byte[] rangeStartKey, byte[] rangeEndKey);
@@ -271,16 +271,16 @@ static String getRegionNameAsString(@CheckForNull RegionInfo ri, byte[] regionNa
   }
 
   /**
-   * @return Return a String of short, printable names for <code>hris</code> (usually encoded name)
-   *         for us logging.
+   * Returns a String of short, printable names for <code>hris</code> (usually encoded name) for us
+   * logging.
    */
   static String getShortNameToLog(RegionInfo... hris) {
     return getShortNameToLog(Arrays.asList(hris));
   }
 
   /**
-   * @return Return a String of short, printable names for <code>hris</code> (usually encoded name)
-   *         for us logging.
+   * Returns a String of short, printable names for <code>hris</code> (usually encoded name) for us
+   * logging.
    */
   static String getShortNameToLog(final List<RegionInfo> ris) {
     return ris.stream().map(RegionInfo::getEncodedName).collect(Collectors.toList()).toString();
@@ -369,8 +369,7 @@ static RegionInfo parseFromOrNull(final byte[] bytes, int offset, int len) {
   }
 
   /**
-   * @param bytes A pb RegionInfo serialized with a pb magic prefix.
-   * @return A deserialized {@link RegionInfo}
+   * Returns A deserialized {@link RegionInfo}
    */
   @InterfaceAudience.Private
   static RegionInfo parseFrom(final byte[] bytes) throws DeserializationException {
@@ -379,6 +378,7 @@ static RegionInfo parseFrom(final byte[] bytes) throws DeserializationException
   }
 
   /**
+   * Parse a serialized representation of {@link RegionInfo}
    * @param bytes  A pb RegionInfo serialized with a pb magic prefix.
    * @param offset starting point in the byte array
    * @param len    length to read on the byte array
@@ -423,7 +423,7 @@ static boolean areAdjacent(RegionInfo regionA, RegionInfo regionB) {
   }
 
   /**
-   * @return This instance serialized as protobuf w/ a magic pb prefix.
+   * Returns This instance serialized as protobuf w/ a magic pb prefix.
    * @see #parseFrom(byte[])
    */
   static byte[] toByteArray(RegionInfo ri) {
@@ -751,7 +751,7 @@ default boolean isLast() {
   }
 
   /**
-   * @return True if region is next, adjacent but 'after' this one.
+   * Returns True if region is next, adjacent but 'after' this one.
    * @see #isAdjacent(RegionInfo)
    * @see #areAdjacent(RegionInfo, RegionInfo)
    */
@@ -760,7 +760,7 @@ default boolean isNext(RegionInfo after) {
   }
 
   /**
-   * @return True if region is adjacent, either just before or just after this one.
+   * Returns True if region is adjacent, either just before or just after this one.
    * @see #isNext(RegionInfo)
    */
   default boolean isAdjacent(RegionInfo other) {
@@ -773,7 +773,7 @@ default boolean isDegenerate() {
   }
 
   /**
-   * @return True if an overlap in region range.
+   * Returns True if an overlap in region range.
    * @see #isDegenerate()
    */
   default boolean isOverlap(RegionInfo other) {
@@ -799,6 +799,7 @@ default boolean isOverlap(RegionInfo other) {
     return Bytes.compareTo(getStartKey(), other.getEndKey()) < 0;
   }
 
+  @Override
   default int compareTo(RegionInfo other) {
     return RegionInfo.COMPARATOR.compare(this, other);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionReplicaUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionReplicaUtil.java
index 4475a01c0f91..1d6708b49d14 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionReplicaUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionReplicaUtil.java
@@ -51,7 +51,7 @@ public class RegionReplicaUtil {
   /**
    * Returns the RegionInfo for the given replicaId. RegionInfo's correspond to a range of a table,
    * but more than one "instance" of the same range can be deployed which are differentiated by the
-   * replicaId. n * @param replicaId the replicaId to use
+   * replicaId.
    * @return an RegionInfo object corresponding to the same range (table, start and end key), but
    *         for the given replicaId.
    */
@@ -149,7 +149,7 @@ public static List<RegionInfo> addReplicas(final List<RegionInfo> regions, int o
     if ((newReplicaCount - 1) <= 0) {
       return regions;
     }
-    List<RegionInfo> hRegionInfos = new ArrayList<>((newReplicaCount) * regions.size());
+    List<RegionInfo> hRegionInfos = new ArrayList<>(newReplicaCount * regions.size());
     for (RegionInfo ri : regions) {
       if (
         RegionReplicaUtil.isDefaultReplica(ri)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionServerCoprocessorRpcChannelImpl.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionServerCoprocessorRpcChannelImpl.java
index 29b092cad883..ed5fd16dab3f 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionServerCoprocessorRpcChannelImpl.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RegionServerCoprocessorRpcChannelImpl.java
@@ -78,11 +78,11 @@ public void callMethod(MethodDescriptor method, RpcController controller, Messag
     Message responsePrototype, RpcCallback<Message> done) {
     addListener(
       callerBuilder.action((c, s) -> rpcCall(method, request, responsePrototype, c, s)).call(),
-      ((r, e) -> {
+      (r, e) -> {
         if (e != null) {
           ((ClientCoprocessorRpcController) controller).setFailed(e);
         }
         done.run(r);
-      }));
+      });
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java
index 1717a9f6964c..a1ab6075fe7b 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java
@@ -894,8 +894,8 @@ public void setStatistics(RegionLoadStats loadStats) {
   }
 
   /**
-   * @return the associated statistics about the region from which this was returned. Can be
-   *         <tt>null</tt> if stats are disabled.
+   * Returns the associated statistics about the region from which this was returned. Can be
+   * <tt>null</tt> if stats are disabled.
    */
   public RegionLoadStats getStats() {
     return stats;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowAccess.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowAccess.java
index cd1f47560798..1af8798fd87c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowAccess.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowAccess.java
@@ -22,7 +22,6 @@
 /**
  * Provide a way to access the inner buffer. The purpose is to reduce the elapsed time to move a
  * large number of elements between collections.
- * @param <T>
  */
 @InterfaceAudience.Private
 public interface RowAccess<T> extends Iterable<T> {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowMutations.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowMutations.java
index 0cf7f69e9b48..be44c26190b1 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowMutations.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RowMutations.java
@@ -70,6 +70,7 @@ public RowMutations(byte[] row, int initialCapacity) {
   }
 
   /**
+   * Add a mutation
    * @param mutation The data to send.
    * @throws IOException if the row of added mutation doesn't match the original row
    */
@@ -78,6 +79,7 @@ public RowMutations add(Mutation mutation) throws IOException {
   }
 
   /**
+   * Add a list of mutations
    * @param mutations The data to send.
    * @throws IOException if the row of added mutation doesn't match the original row
    */
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java
index 7e557fcfdb74..bdca990ca549 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Scan.java
@@ -710,9 +710,9 @@ public Scan setAllowPartialResults(final boolean allowPartialResults) {
   }
 
   /**
-   * @return true when the constructor of this scan understands that the results they will see may
-   *         only represent a partial portion of a row. The entire row would be retrieved by
-   *         subsequent calls to {@link ResultScanner#next()}
+   * Returns true when the constructor of this scan understands that the results they will see may
+   * only represent a partial portion of a row. The entire row would be retrieved by subsequent
+   * calls to {@link ResultScanner#next()}
    */
   public boolean getAllowPartialResults() {
     return allowPartialResults;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScanResultConsumer.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScanResultConsumer.java
index b574b2c2bd5e..44f8e1940459 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScanResultConsumer.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ScanResultConsumer.java
@@ -30,8 +30,7 @@
 public interface ScanResultConsumer extends ScanResultConsumerBase {
 
   /**
-   * @param result the data fetched from HBase service.
-   * @return {@code false} if you want to terminate the scan process. Otherwise {@code true}
+   * Return {@code false} if you want to terminate the scan process. Otherwise {@code true}
    */
   boolean onNext(Result result);
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ServiceCaller.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ServiceCaller.java
index 501f412bc575..fb4acbdf6574 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ServiceCaller.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ServiceCaller.java
@@ -28,20 +28,16 @@
  * Usually, it is just a simple lambda expression, like:
  *
  * <pre>
- * <code>
- * (stub, controller, rpcCallback) -> {
+ * (stub, controller, rpcCallback) -&gt; {
  *   XXXRequest request = ...; // prepare the request
  *   stub.xxx(controller, request, rpcCallback);
  * }
- * </code>
  * </pre>
  *
  * And if already have the {@code request}, the lambda expression will be:
  *
  * <pre>
- * <code>
- * (stub, controller, rpcCallback) -> stub.xxx(controller, request, rpcCallback)
- * </code>
+ * (stub, controller, rpcCallback) -&gt; stub.xxx(controller, request, rpcCallback)
  * </pre>
  *
  * @param <S> the type of the protobuf Service you want to call.
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/SlowLogParams.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/SlowLogParams.java
index 3311539c2614..b1460c0b116c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/SlowLogParams.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/SlowLogParams.java
@@ -62,13 +62,10 @@ public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
-
-    if (o == null || getClass() != o.getClass()) {
+    if (!(o instanceof SlowLogParams)) {
       return false;
     }
-
     SlowLogParams that = (SlowLogParams) o;
-
     return new EqualsBuilder().append(regionName, that.regionName).append(params, that.params)
       .isEquals();
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Table.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Table.java
index 0f93ab21a2c1..53c33a667c3c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Table.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Table.java
@@ -30,7 +30,6 @@
 import org.apache.hadoop.hbase.CompareOperator;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.coprocessor.Batch;
-import org.apache.hadoop.hbase.client.coprocessor.Batch.Callback;
 import org.apache.hadoop.hbase.filter.Filter;
 import org.apache.hadoop.hbase.io.TimeRange;
 import org.apache.hadoop.hbase.ipc.CoprocessorRpcChannel;
@@ -302,11 +301,13 @@ default CheckAndMutateBuilder checkAndMutate(byte[] row, byte[] family) {
   interface CheckAndMutateBuilder {
 
     /**
+     * Specify a column qualifer
      * @param qualifier column qualifier to check.
      */
     CheckAndMutateBuilder qualifier(byte[] qualifier);
 
     /**
+     * Specify a timerange
      * @param timeRange timeRange to check
      */
     CheckAndMutateBuilder timeRange(TimeRange timeRange);
@@ -325,24 +326,28 @@ default CheckAndMutateBuilder ifEquals(byte[] value) {
     }
 
     /**
+     * Check for match.
      * @param compareOp comparison operator to use
      * @param value     the expected value
      */
     CheckAndMutateBuilder ifMatches(CompareOperator compareOp, byte[] value);
 
     /**
+     * Specify a Put to commit if the check succeeds.
      * @param put data to put if check succeeds
      * @return {@code true} if the new put was executed, {@code false} otherwise.
      */
     boolean thenPut(Put put) throws IOException;
 
     /**
+     * Specify a Delete to commit if the check succeeds.
      * @param delete data to delete if check succeeds
      * @return {@code true} if the new delete was executed, {@code false} otherwise.
      */
     boolean thenDelete(Delete delete) throws IOException;
 
     /**
+     * Specify a RowMutations to commit if the check succeeds.
      * @param mutation mutations to perform if check succeeds
      * @return true if the new mutation was executed, false otherwise.
      */
@@ -379,23 +384,27 @@ default CheckAndMutateWithFilterBuilder checkAndMutate(byte[] row, Filter filter
   interface CheckAndMutateWithFilterBuilder {
 
     /**
+     * Specify a timerange.
      * @param timeRange timeRange to check
      */
     CheckAndMutateWithFilterBuilder timeRange(TimeRange timeRange);
 
     /**
+     * Specify a Put to commit if the check succeeds.
      * @param put data to put if check succeeds
      * @return {@code true} if the new put was executed, {@code false} otherwise.
      */
     boolean thenPut(Put put) throws IOException;
 
     /**
+     * Specify a Delete to commit if the check succeeds.
      * @param delete data to delete if check succeeds
      * @return {@code true} if the new delete was executed, {@code false} otherwise.
      */
     boolean thenDelete(Delete delete) throws IOException;
 
     /**
+     * Specify a RowMutations to commit if the check succeeds.
      * @param mutation mutations to perform if check succeeds
      * @return true if the new mutation was executed, false otherwise.
      */
@@ -660,7 +669,7 @@ default <R extends Message> Map<byte[], R> batchCoprocessorService(
     final Map<byte[], R> results =
       Collections.synchronizedMap(new TreeMap<byte[], R>(Bytes.BYTES_COMPARATOR));
     batchCoprocessorService(methodDescriptor, request, startKey, endKey, responsePrototype,
-      new Callback<R>() {
+      new Batch.Callback<R>() {
         @Override
         public void update(byte[] region, byte[] row, R result) {
           if (region != null) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptor.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptor.java
index f960f1c748cb..f500a1128a51 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptor.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptor.java
@@ -267,8 +267,8 @@ public interface TableDescriptor {
   boolean isReadOnly();
 
   /**
-   * @return Name of this table and then a map of all of the column family descriptors (with only
-   *         the non-default column family attributes)
+   * Returns Name of this table and then a map of all of the column family descriptors (with only
+   * the non-default column family attributes)
    */
   String toStringCustomizedValues();
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java
index 3fa39ee8e855..d0d3e36aa8ff 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java
@@ -143,8 +143,6 @@ public class TableDescriptorBuilder {
   private static final Bytes REGION_MEMSTORE_REPLICATION_KEY =
     new Bytes(Bytes.toBytes(REGION_MEMSTORE_REPLICATION));
 
-  private static final Bytes REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY =
-    new Bytes(Bytes.toBytes(RegionReplicaUtil.REGION_REPLICA_WAIT_FOR_PRIMARY_FLUSH_CONF_KEY));
   /**
    * Used by shell/rest interface to access this metadata attribute which denotes if the table
    * should be treated by region normalizer.
@@ -302,10 +300,7 @@ public static PrettyPrinter.Unit getUnit(String key) {
 
   private final ModifyableTableDescriptor desc;
 
-  /**
-   * @param desc The table descriptor to serialize
-   * @return This instance serialized with pb with pb magic prefix
-   */
+  /** Returns This instance serialized with pb with pb magic prefix */
   public static byte[] toByteArray(TableDescriptor desc) {
     if (desc instanceof ModifyableTableDescriptor) {
       return ((ModifyableTableDescriptor) desc).toByteArray();
@@ -317,7 +312,7 @@ public static byte[] toByteArray(TableDescriptor desc) {
    * The input should be created by {@link #toByteArray}.
    * @param pbBytes A pb serialized TableDescriptor instance with pb magic prefix
    * @return This instance serialized with pb with pb magic prefix
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    */
   public static TableDescriptor parseFrom(byte[] pbBytes) throws DeserializationException {
     return ModifyableTableDescriptor.parseFrom(pbBytes);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableOverAsyncTable.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableOverAsyncTable.java
index d4db9eb49e67..e1565f18159a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableOverAsyncTable.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableOverAsyncTable.java
@@ -47,8 +47,7 @@
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.RetriesExhaustedException.ThrowableWithExtraContext;
-import org.apache.hadoop.hbase.client.coprocessor.Batch.Call;
-import org.apache.hadoop.hbase.client.coprocessor.Batch.Callback;
+import org.apache.hadoop.hbase.client.coprocessor.Batch;
 import org.apache.hadoop.hbase.client.trace.TableOperationSpanBuilder;
 import org.apache.hadoop.hbase.filter.Filter;
 import org.apache.hadoop.hbase.io.TimeRange;
@@ -143,8 +142,8 @@ public void batch(List<? extends Row> actions, Object[] results) throws IOExcept
   }
 
   @Override
-  public <R> void batchCallback(List<? extends Row> actions, Object[] results, Callback<R> callback)
-    throws IOException, InterruptedException {
+  public <R> void batchCallback(List<? extends Row> actions, Object[] results,
+    Batch.Callback<R> callback) throws IOException, InterruptedException {
     ConcurrentLinkedQueue<ThrowableWithExtraContext> errors = new ConcurrentLinkedQueue<>();
     CountDownLatch latch = new CountDownLatch(actions.size());
     AsyncTableRegionLocator locator = conn.getRegionLocator(getName());
@@ -467,7 +466,7 @@ private interface StubCall<R> {
   }
 
   private <R> void coprocessorService(String serviceName, byte[] startKey, byte[] endKey,
-    Callback<R> callback, StubCall<R> call) throws Throwable {
+    Batch.Callback<R> callback, StubCall<R> call) throws Throwable {
     // get regions covered by the row range
     ExecutorService pool = Context.current().wrap(this.poolSupplier.get());
     List<byte[]> keys = getStartKeysInRange(startKey, endKey);
@@ -509,7 +508,8 @@ private <R> void coprocessorService(String serviceName, byte[] startKey, byte[]
 
   @Override
   public <T extends Service, R> void coprocessorService(Class<T> service, byte[] startKey,
-    byte[] endKey, Call<T, R> callable, Callback<R> callback) throws ServiceException, Throwable {
+    byte[] endKey, Batch.Call<T, R> callable, Batch.Callback<R> callback)
+    throws ServiceException, Throwable {
     final Supplier<Span> supplier = new TableOperationSpanBuilder(conn)
       .setTableName(table.getName()).setOperation(HBaseSemanticAttributes.Operation.COPROC_EXEC);
     TraceUtil.trace(() -> {
@@ -526,8 +526,8 @@ public <T extends Service, R> void coprocessorService(Class<T> service, byte[] s
   @SuppressWarnings("unchecked")
   @Override
   public <R extends Message> void batchCoprocessorService(MethodDescriptor methodDescriptor,
-    Message request, byte[] startKey, byte[] endKey, R responsePrototype, Callback<R> callback)
-    throws ServiceException, Throwable {
+    Message request, byte[] startKey, byte[] endKey, R responsePrototype,
+    Batch.Callback<R> callback) throws ServiceException, Throwable {
     final Supplier<Span> supplier = new TableOperationSpanBuilder(conn)
       .setTableName(table.getName()).setOperation(HBaseSemanticAttributes.Operation.COPROC_EXEC);
     TraceUtil.trace(() -> {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableState.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableState.java
index 6ecd97a75c9d..4e20302be45e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableState.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableState.java
@@ -209,15 +209,19 @@ public boolean isInStates(State... target) {
 
   @Override
   public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof TableState)) {
+      return false;
+    }
     TableState that = (TableState) o;
-
-    if (state != that.state) return false;
-    if (tableName != null ? !tableName.equals(that.tableName) : that.tableName != null)
+    if (state != that.state) {
       return false;
-
+    }
+    if (tableName != null ? !tableName.equals(that.tableName) : that.tableName != null) {
+      return false;
+    }
     return true;
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ClientBackoffPolicyFactory.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ClientBackoffPolicyFactory.java
index a786702b1693..6993a4ac21a9 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ClientBackoffPolicyFactory.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ClientBackoffPolicyFactory.java
@@ -22,15 +22,11 @@
 import org.apache.hadoop.hbase.util.ReflectionUtils;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public final class ClientBackoffPolicyFactory {
 
-  private static final Logger LOG = LoggerFactory.getLogger(ClientBackoffPolicyFactory.class);
-
   private ClientBackoffPolicyFactory() {
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ExponentialClientBackoffPolicy.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ExponentialClientBackoffPolicy.java
index aa84207e1ed1..0e3339948eaa 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ExponentialClientBackoffPolicy.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/backoff/ExponentialClientBackoffPolicy.java
@@ -21,8 +21,6 @@
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.yetus.audience.InterfaceAudience;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
 
@@ -33,8 +31,6 @@
 @InterfaceAudience.Public
 public class ExponentialClientBackoffPolicy implements ClientBackoffPolicy {
 
-  private static final Logger LOG = LoggerFactory.getLogger(ExponentialClientBackoffPolicy.class);
-
   private static final long ONE_MINUTE = 60 * 1000;
   public static final long DEFAULT_MAX_BACKOFF = 5 * ONE_MINUTE;
   public static final String MAX_BACKOFF_KEY = "hbase.client.exponential-backoff.max";
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/coprocessor/BigDecimalColumnInterpreter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/coprocessor/BigDecimalColumnInterpreter.java
index 900f96440dca..1e42be4baad8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/coprocessor/BigDecimalColumnInterpreter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/coprocessor/BigDecimalColumnInterpreter.java
@@ -80,7 +80,7 @@ public BigDecimal getMaxValue() {
 
   @Override
   public BigDecimal increment(BigDecimal bd) {
-    return bd == null ? null : (bd.add(BigDecimal.ONE));
+    return bd == null ? null : bd.add(BigDecimal.ONE);
   }
 
   @Override
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/replication/ReplicationPeerConfigUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/replication/ReplicationPeerConfigUtil.java
index 4145a348b08c..b2ddc4eaec15 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/replication/ReplicationPeerConfigUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/replication/ReplicationPeerConfigUtil.java
@@ -22,6 +22,7 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -113,8 +114,8 @@ public static ReplicationProtos.TableCF[] convert(String tableCFsConfig) {
     }
 
     ReplicationProtos.TableCF.Builder tableCFBuilder = ReplicationProtos.TableCF.newBuilder();
-    String[] tables = tableCFsConfig.split(";");
-    List<ReplicationProtos.TableCF> tableCFList = new ArrayList<>(tables.length);
+    List<String> tables = Splitter.on(';').splitToList(tableCFsConfig);
+    List<ReplicationProtos.TableCF> tableCFList = new ArrayList<>(tables.size());
 
     for (String tab : tables) {
       // 1 ignore empty table config
@@ -124,9 +125,9 @@ public static ReplicationProtos.TableCF[] convert(String tableCFsConfig) {
       }
       // 2 split to "table" and "cf1,cf2"
       // for each table: "table#cf1,cf2" or "table"
-      String[] pair = tab.split(":");
-      String tabName = pair[0].trim();
-      if (pair.length > 2 || tabName.length() == 0) {
+      Iterator<String> i = Splitter.on(':').split(tab).iterator();
+      String tabName = i.next().trim();
+      if (tabName.length() == 0) {
         LOG.info("incorrect format:" + tableCFsConfig);
         continue;
       }
@@ -135,16 +136,17 @@ public static ReplicationProtos.TableCF[] convert(String tableCFsConfig) {
       // split namespace from tableName
       String ns = "default";
       String tName = tabName;
-      String[] dbs = tabName.split("\\.");
-      if (dbs != null && dbs.length == 2) {
-        ns = dbs[0];
-        tName = dbs[1];
+      List<String> dbs = Splitter.on('.').splitToList(tabName);
+      if (dbs != null && dbs.size() == 2) {
+        Iterator<String> ii = dbs.iterator();
+        ns = ii.next();
+        tName = ii.next();
       }
       tableCFBuilder.setTableName(ProtobufUtil.toProtoTableName(TableName.valueOf(ns, tName)));
 
       // 3 parse "cf1,cf2" part to List<cf>
-      if (pair.length == 2) {
-        String[] cfsList = pair[1].split(",");
+      if (i.hasNext()) {
+        List<String> cfsList = Splitter.on(',').splitToList(i.next());
         for (String cf : cfsList) {
           String cfName = cf.trim();
           if (cfName.length() > 0) {
@@ -241,6 +243,7 @@ public static Map<TableName, List<String>> convert2Map(ReplicationProtos.TableCF
   }
 
   /**
+   * Parse the serialized representation of a peer configuration.
    * @param bytes Content of a peer znode.
    * @return ClusterKey parsed from the passed bytes.
    * @throws DeserializationException deserialization exception
@@ -384,10 +387,9 @@ public static ReplicationProtos.ReplicationPeer convert(ReplicationPeerConfig pe
   }
 
   /**
-   * @param peerConfig peer config of replication peer
-   * @return Serialized protobuf of <code>peerConfig</code> with pb magic prefix prepended suitable
-   *         for use as content of a this.peersZNode; i.e. the content of PEER_ID znode under
-   *         /hbase/replication/peers/PEER_ID
+   * Returns Serialized protobuf of <code>peerConfig</code> with pb magic prefix prepended suitable
+   * for use as content of a this.peersZNode; i.e. the content of PEER_ID znode under
+   * /hbase/replication/peers/PEER_ID
    */
   public static byte[] toByteArray(final ReplicationPeerConfig peerConfig) {
     byte[] bytes = convert(peerConfig).toByteArray();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
index 0e24e0c98143..af9f5d9ff444 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
@@ -40,11 +40,6 @@
  * {@link ColumnInterpreter#castToReturnType(Object)} which takes a &lt;T&gt; type and returns a
  * &lt;S&gt; type. The AggregateIm&gt;lementation uses PB messages to initialize the user's
  * ColumnInterpreter implementation, and for sending the responses back to AggregationClient.
- * @param T Cell value data type
- * @param S Promoted data type
- * @param P PB message that is used to transport initializer specific bytes
- * @param Q PB message that is used to transport Cell (&lt;T&gt;) instance
- * @param R PB message that is used to transport Promoted (&lt;S&gt;) instance
  */
 @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
 @InterfaceStability.Evolving
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/exceptions/RegionOpeningException.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/exceptions/RegionOpeningException.java
index 347c6b987a15..bef80b2cb82d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/exceptions/RegionOpeningException.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/exceptions/RegionOpeningException.java
@@ -20,8 +20,6 @@
 import org.apache.hadoop.hbase.NotServingRegionException;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Subclass if the server knows the region is now on another server. This allows the client to call
@@ -30,7 +28,7 @@
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class RegionOpeningException extends NotServingRegionException {
-  private static final Logger LOG = LoggerFactory.getLogger(RegionOpeningException.class);
+
   private static final long serialVersionUID = -7232903522310558395L;
 
   public RegionOpeningException(String message) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
index 669a591a961c..f3ec888f9c9e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
@@ -82,9 +82,9 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link BigDecimalComparator}
    * @param pbBytes A pb serialized {@link BigDecimalComparator} instance
    * @return An instance of {@link BigDecimalComparator} made from <code>bytes</code>
-   * @throws DeserializationException A deserialization exception
    * @see #toByteArray
    */
   public static BigDecimalComparator parseFrom(final byte[] pbBytes)
@@ -100,10 +100,10 @@ public static BigDecimalComparator parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param other the other comparator
-   * @return true if and only if the fields of the comparator that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
+  @SuppressWarnings("ReferenceEquality")
   boolean areSerializedFieldsEqual(BigDecimalComparator other) {
     if (other == this) {
       return true;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
index 7aff979f4c2d..749d055f8ebd 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
@@ -64,9 +64,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link BinaryComparator}
    * @param pbBytes A pb serialized {@link BinaryComparator} instance
-   * @return An instance of {@link BinaryComparator} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link BinaryComparator} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static BinaryComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
     ComparatorProtos.BinaryComparator proto;
@@ -79,14 +80,17 @@ public static BinaryComparator parseFrom(final byte[] pbBytes) throws Deserializ
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof BinaryComparator)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof BinaryComparator)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(other);
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
index 8ce0092e7509..1e2250fda45c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
@@ -86,9 +86,9 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link BinaryComponentComparator}
    * @param pbBytes A pb serialized {@link BinaryComponentComparator} instance
    * @return An instance of {@link BinaryComponentComparator} made from <code>bytes</code>
-   * @throws DeserializationException DeserializationException
    * @see #toByteArray
    */
   public static BinaryComponentComparator parseFrom(final byte[] pbBytes)
@@ -103,9 +103,8 @@ public static BinaryComponentComparator parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param other paramemter to compare against
-   * @return true if and only if the fields of the comparator that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
index fcf447dcb0ca..00e5fdd7a4e7 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
@@ -68,9 +68,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link BinaryPrefixComparator}
    * @param pbBytes A pb serialized {@link BinaryPrefixComparator} instance
-   * @return An instance of {@link BinaryPrefixComparator} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link BinaryPrefixComparator} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static BinaryPrefixComparator parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -84,14 +85,17 @@ public static BinaryPrefixComparator parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof BinaryPrefixComparator)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof BinaryPrefixComparator)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(other);
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
index 8abdcf4e8a6c..f421214411b8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
@@ -74,8 +74,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link BitComparator}
    * @param pbBytes A pb serialized {@link BitComparator} instance
-   * @return An instance of {@link BitComparator} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link BitComparator} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static BitComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
     ComparatorProtos.BitComparator proto;
@@ -89,14 +91,17 @@ public static BitComparator parseFrom(final byte[] pbBytes) throws Deserializati
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof BitComparator)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof BitComparator)) {
+      return false;
+    }
     BitComparator comparator = (BitComparator) other;
     return super.areSerializedFieldsEqual(other)
       && this.getOperator().equals(comparator.getOperator());
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
index 513f4b1e2dbd..d15b5c5bbae7 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
@@ -88,6 +88,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link ColumnCountGetFilter}
    * @param pbBytes A pb serialized {@link ColumnCountGetFilter} instance
    * @return An instance of {@link ColumnCountGetFilter} made from <code>bytes</code>
    * @see #toByteArray
@@ -104,15 +105,17 @@ public static ColumnCountGetFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof ColumnCountGetFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof ColumnCountGetFilter)) {
+      return false;
+    }
     ColumnCountGetFilter other = (ColumnCountGetFilter) o;
     return this.getLimit() == other.getLimit();
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
index 94f7d76682cf..cf29cf02a38d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
@@ -78,23 +78,14 @@ public ColumnPaginationFilter(final int limit, final byte[] columnOffset) {
     this.columnOffset = columnOffset;
   }
 
-  /**
-   * n
-   */
   public int getLimit() {
     return limit;
   }
 
-  /**
-   * n
-   */
   public int getOffset() {
     return offset;
   }
 
-  /**
-   * n
-   */
   public byte[] getColumnOffset() {
     return columnOffset;
   }
@@ -167,9 +158,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link ColumnPaginationFilter}
    * @param pbBytes A pb serialized {@link ColumnPaginationFilter} instance
-   * @return An instance of {@link ColumnPaginationFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link ColumnPaginationFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static ColumnPaginationFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -186,15 +178,17 @@ public static ColumnPaginationFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof ColumnPaginationFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof ColumnPaginationFilter)) {
+      return false;
+    }
     ColumnPaginationFilter other = (ColumnPaginationFilter) o;
     if (this.columnOffset != null) {
       return this.getLimit() == other.getLimit()
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
index 5ca97e880bae..209b5d72f6ea 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
@@ -111,9 +111,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parses a serialized representation of the {@link ColumnPrefixFilter}
    * @param pbBytes A pb serialized {@link ColumnPrefixFilter} instance
    * @return An instance of {@link ColumnPrefixFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static ColumnPrefixFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -127,15 +128,17 @@ public static ColumnPrefixFilter parseFrom(final byte[] pbBytes) throws Deserial
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof ColumnPrefixFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof ColumnPrefixFilter)) {
+      return false;
+    }
     ColumnPrefixFilter other = (ColumnPrefixFilter) o;
     return Bytes.equals(this.getPrefix(), other.getPrefix());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
index 2aafd300e03a..300e3dcd2552 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
@@ -157,9 +157,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link ColumnRangeFilter}
    * @param pbBytes A pb serialized {@link ColumnRangeFilter} instance
-   * @return An instance of {@link ColumnRangeFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link ColumnRangeFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static ColumnRangeFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.ColumnRangeFilter proto;
@@ -175,9 +176,8 @@ public static ColumnRangeFilter parseFrom(final byte[] pbBytes) throws Deseriali
   }
 
   /**
-   * @param o filter to serialize.
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
index 0b3b85dbb478..2ee5ac31748a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
@@ -168,10 +168,9 @@ FilterProtos.ColumnValueFilter convert() {
   }
 
   /**
-   * Parse protobuf bytes to a ColumnValueFilter
-   * @param pbBytes pbBytes
-   * @return a ColumnValueFilter
-   * @throws DeserializationException deserialization exception
+   * Parse a serialized representation of {@link ColumnValueFilter}
+   * @param pbBytes A pb serialized {@link ColumnValueFilter} instance
+   * @return An instance of {@link ColumnValueFilter} made from <code>bytes</code>
    */
   public static ColumnValueFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.ColumnValueFilter proto;
@@ -198,6 +197,10 @@ public byte[] toByteArray() throws IOException {
     return convert().toByteArray();
   }
 
+  /**
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
+   */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
     if (o == this) {
@@ -205,7 +208,6 @@ boolean areSerializedFieldsEqual(Filter o) {
     } else if (!(o instanceof ColumnValueFilter)) {
       return false;
     }
-
     ColumnValueFilter other = (ColumnValueFilter) o;
     return Bytes.equals(this.getFamily(), other.getFamily())
       && Bytes.equals(this.getQualifier(), other.getQualifier())
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/CompareFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/CompareFilter.java
index 8e994a9feb54..9cbd81b678ae 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/CompareFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/CompareFilter.java
@@ -136,7 +136,7 @@ static boolean compare(final CompareOperator op, int compareResult) {
     }
   }
 
-  // returns an array of heterogeneous objects
+  /** Returns an array of heterogeneous objects */
   public static ArrayList<Object> extractArguments(ArrayList<byte[]> filterArguments) {
     Preconditions.checkArgument(filterArguments.size() == 2, "Expected 2 but got: %s",
       filterArguments.size());
@@ -166,13 +166,17 @@ FilterProtos.CompareFilter convert() {
   }
 
   /**
-   * n * @return true if and only if the fields of the filter that are serialized are equal to the
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
    * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof CompareFilter)) return false;
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof CompareFilter)) {
+      return false;
+    }
     CompareFilter other = (CompareFilter) o;
     return this.getCompareOperator().equals(other.getCompareOperator())
       && (this.getComparator() == other.getComparator()
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
index da613c7f3d02..5c5fa3813645 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
@@ -199,9 +199,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a seralized representation of {@link DependentColumnFilter}
    * @param pbBytes A pb serialized {@link DependentColumnFilter} instance
-   * @return An instance of {@link DependentColumnFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link DependentColumnFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static DependentColumnFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -228,16 +229,19 @@ public static DependentColumnFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * n * @return true if and only if the fields of the filter that are serialized are equal to the
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
    * corresponding fields in other. Used for testing.
    */
   @edu.umd.cs.findbugs.annotations.SuppressWarnings(
       value = "RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE")
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof DependentColumnFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof DependentColumnFilter)) {
+      return false;
+    }
     DependentColumnFilter other = (DependentColumnFilter) o;
     return other != null && super.areSerializedFieldsEqual(other)
       && Bytes.equals(this.getFamily(), other.getFamily())
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
index 96122e84dde5..5991752ac898 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
@@ -82,6 +82,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse the serialized representation of {@link FamilyFilter}
    * @param pbBytes A pb serialized {@link FamilyFilter} instance
    * @return An instance of {@link FamilyFilter} made from <code>bytes</code> n * @see #toByteArray
    */
@@ -106,14 +107,17 @@ public static FamilyFilter parseFrom(final byte[] pbBytes) throws Deserializatio
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof FamilyFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof FamilyFilter)) {
+      return false;
+    }
     FamilyFilter other = (FamilyFilter) o;
     return super.areSerializedFieldsEqual(other);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
index 2c623306ba0b..2d6882559e59 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
@@ -216,7 +216,6 @@ public static Filter parseFrom(final byte[] pbBytes) throws DeserializationExcep
    * Concrete implementers can signal a failure condition in their code by throwing an
    * {@link IOException}. n * @return true if and only if the fields of the filter that are
    * serialized are equal to the corresponding fields in other. Used for testing.
-   * @throws IOException in case an I/O or an filter specific failure needs to be signaled.
    */
   abstract boolean areSerializedFieldsEqual(Filter other);
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
index 8dc66182d8c7..d9a817088d7c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
@@ -194,8 +194,10 @@ public byte[] toByteArray() throws IOException {
   }
 
   /**
+   * Parse a seralized representation of {@link FilterList}
    * @param pbBytes A pb serialized {@link FilterList} instance
-   * @return An instance of {@link FilterList} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link FilterList} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static FilterList parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.FilterList proto;
@@ -218,14 +220,17 @@ public static FilterList parseFrom(final byte[] pbBytes) throws DeserializationE
   }
 
   /**
-   * n * @return true if and only if the fields of the filter that are serialized are equal to the
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
    * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter other) {
-    if (other == this) return true;
-    if (!(other instanceof FilterList)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof FilterList)) {
+      return false;
+    }
     FilterList o = (FilterList) other;
     return this.getOperator().equals(o.getOperator())
       && ((this.getFilters() == o.getFilters()) || this.getFilters().equals(o.getFilters()));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithAND.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithAND.java
index 760b79d497d3..45e06f444547 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithAND.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithAND.java
@@ -270,12 +270,12 @@ public Cell getNextCellHint(Cell currentCell) throws IOException {
 
   @Override
   public boolean equals(Object obj) {
-    if (!(obj instanceof FilterListWithAND)) {
-      return false;
-    }
     if (this == obj) {
       return true;
     }
+    if (!(obj instanceof FilterListWithAND)) {
+      return false;
+    }
     FilterListWithAND f = (FilterListWithAND) obj;
     return this.filters.equals(f.getFilters()) && this.seekHintFilters.equals(f.seekHintFilters);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithOR.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithOR.java
index dd50a1bbb8d9..fbe68ab13527 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithOR.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterListWithOR.java
@@ -394,12 +394,12 @@ public Cell getNextCellHint(Cell currentCell) throws IOException {
 
   @Override
   public boolean equals(Object obj) {
-    if (obj == null || (!(obj instanceof FilterListWithOR))) {
-      return false;
-    }
     if (this == obj) {
       return true;
     }
+    if (!(obj instanceof FilterListWithOR)) {
+      return false;
+    }
     FilterListWithOR f = (FilterListWithOR) obj;
     return this.filters.equals(f.getFilters()) && this.prevFilterRCList.equals(f.prevFilterRCList)
       && this.prevCellList.equals(f.prevCellList);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
index d4797aa15e7e..e2fa95c33452 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
@@ -19,7 +19,6 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Objects;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.exceptions.DeserializationException;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -71,6 +70,7 @@ protected boolean hasFoundKV() {
   }
 
   /**
+   * Set or clear the indication if the first KV has been found.
    * @param value update {@link #foundKV} flag with value.
    */
   protected void setFoundKV(boolean value) {
@@ -85,9 +85,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link FirstKeyOnlyFilter}
    * @param pbBytes A pb serialized {@link FirstKeyOnlyFilter} instance
    * @return An instance of {@link FirstKeyOnlyFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static FirstKeyOnlyFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -102,15 +103,17 @@ public static FirstKeyOnlyFilter parseFrom(final byte[] pbBytes) throws Deserial
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof FirstKeyOnlyFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof FirstKeyOnlyFilter)) {
+      return false;
+    }
     return true;
   }
 
@@ -121,6 +124,6 @@ public boolean equals(Object obj) {
 
   @Override
   public int hashCode() {
-    return Objects.hashCode(foundKV);
+    return Boolean.hashCode(foundKV);
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
index cec4a2f06ff2..162b61c8934c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
@@ -32,9 +32,11 @@
 public class FirstKeyValueMatchingQualifiersFilter extends FirstKeyOnlyFilter {
 
   /**
+   * Parses a serialized representation of {@link FirstKeyValueMatchingQualifiersFilter}
    * @param pbBytes A pb serialized {@link FirstKeyValueMatchingQualifiersFilter} instance
    * @return An instance of {@link FirstKeyValueMatchingQualifiersFilter} made from
-   *         <code>bytes</code> n * @see #toByteArray
+   *         <code>bytes</code>
+   * @see #toByteArray
    */
   public static FirstKeyValueMatchingQualifiersFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
index c9d9fd418326..5726413d7649 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
@@ -265,9 +265,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link FuzzyRowFilter}
    * @param pbBytes A pb serialized {@link FuzzyRowFilter} instance
-   * @return An instance of {@link FuzzyRowFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link FuzzyRowFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static FuzzyRowFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.FuzzyRowFilter proto;
@@ -340,7 +341,7 @@ static SatisfiesCode satisfies(boolean reverse, byte[] row, int offset, int leng
       long fuzzyBytes = Bytes.toLong(fuzzyKeyBytes, i);
       long fuzzyMeta = Bytes.toLong(fuzzyKeyMeta, i);
       long rowValue = Bytes.toLong(row, offset + i);
-      if ((rowValue & fuzzyMeta) != (fuzzyBytes)) {
+      if ((rowValue & fuzzyMeta) != fuzzyBytes) {
         // We always return NEXT_EXISTS
         return SatisfiesCode.NEXT_EXISTS;
       }
@@ -352,7 +353,7 @@ static SatisfiesCode satisfies(boolean reverse, byte[] row, int offset, int leng
       int fuzzyBytes = Bytes.toInt(fuzzyKeyBytes, off);
       int fuzzyMeta = Bytes.toInt(fuzzyKeyMeta, off);
       int rowValue = Bytes.toInt(row, offset + off);
-      if ((rowValue & fuzzyMeta) != (fuzzyBytes)) {
+      if ((rowValue & fuzzyMeta) != fuzzyBytes) {
         // We always return NEXT_EXISTS
         return SatisfiesCode.NEXT_EXISTS;
       }
@@ -363,7 +364,7 @@ static SatisfiesCode satisfies(boolean reverse, byte[] row, int offset, int leng
       short fuzzyBytes = Bytes.toShort(fuzzyKeyBytes, off);
       short fuzzyMeta = Bytes.toShort(fuzzyKeyMeta, off);
       short rowValue = Bytes.toShort(row, offset + off);
-      if ((rowValue & fuzzyMeta) != (fuzzyBytes)) {
+      if ((rowValue & fuzzyMeta) != fuzzyBytes) {
         // We always return NEXT_EXISTS
         // even if it does not (in this case getNextForFuzzyRule
         // will return null)
@@ -376,7 +377,7 @@ static SatisfiesCode satisfies(boolean reverse, byte[] row, int offset, int leng
       int fuzzyBytes = fuzzyKeyBytes[off] & 0xff;
       int fuzzyMeta = fuzzyKeyMeta[off] & 0xff;
       int rowValue = row[offset + off] & 0xff;
-      if ((rowValue & fuzzyMeta) != (fuzzyBytes)) {
+      if ((rowValue & fuzzyMeta) != fuzzyBytes) {
         // We always return NEXT_EXISTS
         return SatisfiesCode.NEXT_EXISTS;
       }
@@ -603,14 +604,17 @@ private static byte[] trimTrailingZeroes(byte[] result, byte[] fuzzyKeyMeta, int
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof FuzzyRowFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof FuzzyRowFilter)) {
+      return false;
+    }
     FuzzyRowFilter other = (FuzzyRowFilter) o;
     if (this.fuzzyKeysData.size() != other.fuzzyKeysData.size()) return false;
     for (int i = 0; i < fuzzyKeysData.size(); ++i) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
index 427617120347..c365e94cfbd2 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
@@ -86,9 +86,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link InclusiveStopFilter}
    * @param pbBytes A pb serialized {@link InclusiveStopFilter} instance
-   * @return An instance of {@link InclusiveStopFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link InclusiveStopFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static InclusiveStopFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -103,15 +104,17 @@ public static InclusiveStopFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof InclusiveStopFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof InclusiveStopFilter)) {
+      return false;
+    }
     InclusiveStopFilter other = (InclusiveStopFilter) o;
     return Bytes.equals(this.getStopRowKey(), other.getStopRowKey());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
index 414818a3afc7..47a586a5a2af 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
@@ -102,8 +102,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link KeyOnlyFilter}
    * @param pbBytes A pb serialized {@link KeyOnlyFilter} instance
-   * @return An instance of {@link KeyOnlyFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link KeyOnlyFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static KeyOnlyFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.KeyOnlyFilter proto;
@@ -116,15 +118,17 @@ public static KeyOnlyFilter parseFrom(final byte[] pbBytes) throws Deserializati
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof KeyOnlyFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof KeyOnlyFilter)) {
+      return false;
+    }
     KeyOnlyFilter other = (KeyOnlyFilter) o;
     return this.lenAsVal == other.lenAsVal;
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
index 8f9a7f1dfc3b..bc7d23ae1d02 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
@@ -62,9 +62,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parses a serialized representation of {@link LongComparator}
    * @param pbBytes A pb serialized {@link LongComparator} instance
    * @return An instance of {@link LongComparator} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static LongComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -78,11 +79,16 @@ public static LongComparator parseFrom(final byte[] pbBytes) throws Deserializat
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   boolean areSerializedFieldsEqual(LongComparator other) {
-    if (other == this) return true;
+    if (other == this) {
+      return true;
+    }
+    if (other == null) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(other);
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
index c4676910c14a..3526bbcb0684 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
@@ -197,9 +197,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link MultiRowRangeFilter}
    * @param pbBytes A pb serialized instance
-   * @return An instance of MultiRowRangeFilter
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @return An instance of {@link MultiRowRangeFilter}
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    */
   public static MultiRowRangeFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -224,15 +225,17 @@ public static MultiRowRangeFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param o the filter to compare
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof MultiRowRangeFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof MultiRowRangeFilter)) {
+      return false;
+    }
     MultiRowRangeFilter other = (MultiRowRangeFilter) o;
     if (this.rangeList.size() != other.rangeList.size()) return false;
     for (int i = 0; i < rangeList.size(); ++i) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
index 4a969c0006ee..456290aaae0e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
@@ -128,9 +128,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link MultipleColumnPrefixFilter}
    * @param pbBytes A pb serialized {@link MultipleColumnPrefixFilter} instance
-   * @return An instance of {@link MultipleColumnPrefixFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link MultipleColumnPrefixFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static MultipleColumnPrefixFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -150,15 +151,17 @@ public static MultipleColumnPrefixFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof MultipleColumnPrefixFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof MultipleColumnPrefixFilter)) {
+      return false;
+    }
     MultipleColumnPrefixFilter other = (MultipleColumnPrefixFilter) o;
     return this.sortedPrefixes.equals(other.sortedPrefixes);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
index 6153e1e80800..b7597771458a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
@@ -71,9 +71,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse the serialized representation of {@link NullComparator}
    * @param pbBytes A pb serialized {@link NullComparator} instance
-   * @return An instance of {@link NullComparator} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link NullComparator} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static NullComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
     try {
@@ -86,14 +87,17 @@ public static NullComparator parseFrom(final byte[] pbBytes) throws Deserializat
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof NullComparator)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof NullComparator)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(other);
   }
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
index 087957fafc66..5039dde14ec8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
@@ -100,8 +100,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link PageFilter}
    * @param pbBytes A pb serialized {@link PageFilter} instance
-   * @return An instance of {@link PageFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link PageFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static PageFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.PageFilter proto;
@@ -114,9 +116,8 @@ public static PageFilter parseFrom(final byte[] pbBytes) throws DeserializationE
   }
 
   /**
-   * @param o other Filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
index b08ce971c213..9951330f4535 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
@@ -109,6 +109,7 @@ public Filter parseFilterString(String filterString) throws CharacterCodingExcep
    * @param filterStringAsByteArray filter string given by the user
    * @return filter object we constructed
    */
+  @SuppressWarnings("JdkObsolete")
   public Filter parseFilterString(byte[] filterStringAsByteArray) throws CharacterCodingException {
     // stack for the operators and parenthesis
     Stack<ByteBuffer> operatorStack = new Stack<>();
@@ -156,7 +157,7 @@ public Filter parseFilterString(byte[] filterStringAsByteArray) throws Character
           operatorStack.pop();
           continue;
         }
-        while (!(argumentOnTopOfStack.equals(ParseConstants.LPAREN_BUFFER))) {
+        while (!argumentOnTopOfStack.equals(ParseConstants.LPAREN_BUFFER)) {
           filterStack.push(popArguments(operatorStack, filterStack));
           if (operatorStack.empty()) {
             throw new IllegalArgumentException("Mismatched parenthesis");
@@ -367,7 +368,7 @@ public static ArrayList<byte[]> getFilterArguments(byte[] filterStringAsByteArra
   public void reduce(Stack<ByteBuffer> operatorStack, Stack<Filter> filterStack,
     ByteBuffer operator) {
     while (
-      !operatorStack.empty() && !(ParseConstants.LPAREN_BUFFER.equals(operatorStack.peek()))
+      !operatorStack.empty() && !ParseConstants.LPAREN_BUFFER.equals(operatorStack.peek())
         && hasHigherPriority(operatorStack.peek(), operator)
     ) {
       filterStack.push(popArguments(operatorStack, filterStack));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
index 407b92a8604c..e50e462187e8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
@@ -110,9 +110,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link PrefixFilter}
    * @param pbBytes A pb serialized {@link PrefixFilter} instance
    * @return An instance of {@link PrefixFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static PrefixFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -126,15 +127,17 @@ public static PrefixFilter parseFrom(final byte[] pbBytes) throws Deserializatio
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof PrefixFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof PrefixFilter)) {
+      return false;
+    }
     PrefixFilter other = (PrefixFilter) o;
     return Bytes.equals(this.getPrefix(), other.getPrefix());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
index f8dc591b19a0..baf13eda2fae 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
@@ -76,9 +76,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link QualifierFilter}
    * @param pbBytes A pb serialized {@link QualifierFilter} instance
    * @return An instance of {@link QualifierFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static QualifierFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -102,14 +103,17 @@ public static QualifierFilter parseFrom(final byte[] pbBytes) throws Deserializa
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof QualifierFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof QualifierFilter)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(o);
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
index 5340ecf3434e..d68a4d07bd89 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
@@ -107,9 +107,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link RandomRowFilter}
    * @param pbBytes A pb serialized {@link RandomRowFilter} instance
-   * @return An instance of {@link RandomRowFilter} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link RandomRowFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static RandomRowFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.RandomRowFilter proto;
@@ -122,15 +123,17 @@ public static RandomRowFilter parseFrom(final byte[] pbBytes) throws Deserializa
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof RandomRowFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof RandomRowFilter)) {
+      return false;
+    }
     RandomRowFilter other = (RandomRowFilter) o;
     return this.getChance() == other.getChance();
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
index 4bdc057bd9ea..9c9ccf5d049d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
@@ -152,9 +152,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link RegexStringComparator}
    * @param pbBytes A pb serialized {@link RegexStringComparator} instance
-   * @return An instance of {@link RegexStringComparator} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link RegexStringComparator} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static RegexStringComparator parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -183,13 +184,17 @@ public static RegexStringComparator parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof RegexStringComparator)) return false;
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof RegexStringComparator)) {
+      return false;
+    }
     RegexStringComparator comparator = (RegexStringComparator) other;
     return super.areSerializedFieldsEqual(comparator)
       && engine.getClass().isInstance(comparator.getEngine())
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
index c6c0099a9d0b..51a1c49ff143 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
@@ -96,6 +96,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link RowFilter}
    * @param pbBytes A pb serialized {@link RowFilter} instance
    * @return An instance of {@link RowFilter} made from <code>bytes</code> n * @see #toByteArray
    */
@@ -120,14 +121,17 @@ public static RowFilter parseFrom(final byte[] pbBytes) throws DeserializationEx
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof RowFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof RowFilter)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(o);
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
index f9b80ee72c5e..2aedca5bfbdb 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
@@ -122,9 +122,10 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link SingleColumnValueExcludeFilter}
    * @param pbBytes A pb serialized {@link SingleColumnValueExcludeFilter} instance
-   * @return An instance of {@link SingleColumnValueExcludeFilter} made from <code>bytes</code> n
-   *         * @see #toByteArray
+   * @return An instance of {@link SingleColumnValueExcludeFilter} made from <code>bytes</code>
+   * @see #toByteArray
    */
   public static SingleColumnValueExcludeFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -151,14 +152,17 @@ public static SingleColumnValueExcludeFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof SingleColumnValueExcludeFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof SingleColumnValueExcludeFilter)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(o);
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
index 9806f6387a0b..964a04429c52 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
@@ -284,6 +284,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link SingleColumnValueFilter}
    * @param pbBytes A pb serialized {@link SingleColumnValueFilter} instance
    * @return An instance of {@link SingleColumnValueFilter} made from <code>bytes</code>
    * @see #toByteArray
@@ -312,8 +313,8 @@ public static SingleColumnValueFilter parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
index 08e21fa70c2c..9d2bf1adefc7 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
@@ -105,6 +105,7 @@ public byte[] toByteArray() throws IOException {
   }
 
   /**
+   * Parse a serialized representation of {@link SkipFilter}
    * @param pbBytes A pb serialized {@link SkipFilter} instance
    * @return An instance of {@link SkipFilter} made from <code>bytes</code> n * @see #toByteArray
    */
@@ -123,15 +124,17 @@ public static SkipFilter parseFrom(final byte[] pbBytes) throws DeserializationE
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof SkipFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof SkipFilter)) {
+      return false;
+    }
     SkipFilter other = (SkipFilter) o;
     return getFilter().areSerializedFieldsEqual(other.getFilter());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
index b5fe22dca240..995b37c3f2ff 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
@@ -76,6 +76,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link SubstringComparator}
    * @param pbBytes A pb serialized {@link SubstringComparator} instance
    * @return An instance of {@link SubstringComparator} made from <code>bytes</code> n * @see
    *         #toByteArray
@@ -92,14 +93,17 @@ public static SubstringComparator parseFrom(final byte[] pbBytes)
   }
 
   /**
-   * n * @return true if and only if the fields of the comparator that are serialized are equal to
-   * the corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the comparator that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(ByteArrayComparable other) {
-    if (other == this) return true;
-    if (!(other instanceof SubstringComparator)) return false;
-
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof SubstringComparator)) {
+      return false;
+    }
     SubstringComparator comparator = (SubstringComparator) other;
     return super.areSerializedFieldsEqual(comparator) && this.substr.equals(comparator.substr);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
index 853555ef5112..62512fc128af 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
@@ -167,6 +167,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link TimestampsFilter}
    * @param pbBytes A pb serialized {@link TimestampsFilter} instance
    * @return An instance of {@link TimestampsFilter} made from <code>bytes</code>
    * @see #toByteArray
@@ -183,15 +184,17 @@ public static TimestampsFilter parseFrom(final byte[] pbBytes) throws Deserializ
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof TimestampsFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof TimestampsFilter)) {
+      return false;
+    }
     TimestampsFilter other = (TimestampsFilter) o;
     return this.getTimestamps().equals(other.getTimestamps());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
index 90dda21eb524..a2d00930992b 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
@@ -78,6 +78,7 @@ public byte[] toByteArray() {
   }
 
   /**
+   * Parse a serialized representation of {@link ValueFilter}
    * @param pbBytes A pb serialized {@link ValueFilter} instance
    * @return An instance of {@link ValueFilter} made from <code>bytes</code> n * @see #toByteArray
    */
@@ -102,14 +103,17 @@ public static ValueFilter parseFrom(final byte[] pbBytes) throws Deserialization
   }
 
   /**
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Returns true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof ValueFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof ValueFilter)) {
+      return false;
+    }
     return super.areSerializedFieldsEqual(o);
   }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
index 5d6842b15e45..aae09bee1806 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
@@ -103,9 +103,10 @@ public byte[] toByteArray() throws IOException {
   }
 
   /**
+   * Parse a serialized representation of {@link WhileMatchFilter}
    * @param pbBytes A pb serialized {@link WhileMatchFilter} instance
    * @return An instance of {@link WhileMatchFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
+   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static WhileMatchFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
@@ -123,15 +124,17 @@ public static WhileMatchFilter parseFrom(final byte[] pbBytes) throws Deserializ
   }
 
   /**
-   * @param o the other filter to compare with
-   * @return true if and only if the fields of the filter that are serialized are equal to the
-   *         corresponding fields in other. Used for testing.
+   * Return true if and only if the fields of the filter that are serialized are equal to the
+   * corresponding fields in other. Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
-    if (o == this) return true;
-    if (!(o instanceof WhileMatchFilter)) return false;
-
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof WhileMatchFilter)) {
+      return false;
+    }
     WhileMatchFilter other = (WhileMatchFilter) o;
     return getFilter().areSerializedFieldsEqual(other.getFilter());
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/package-info.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/package-info.java
index 9dea2548ea90..e4d3ab947daf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/package-info.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/package-info.java
@@ -20,15 +20,14 @@
 /**
  * Provides row-level filters applied to HRegion scan results during calls to
  * {@link org.apache.hadoop.hbase.client.ResultScanner#next()}.
-
-<p>
-Filters run the extent of a table unless you wrap your filter in a
-{@link org.apache.hadoop.hbase.filter.WhileMatchFilter}.
-The latter returns as soon as the filter stops matching.
-</p>
-<p>Do not rely on filters carrying state across rows; its not reliable in current
-hbase as we have no handlers in place for when regions split, close or server
-crashes.
-</p>
-*/
+ *
+ * <p>
+ * Filters run the extent of a table unless you wrap your filter in a
+ * {@link org.apache.hadoop.hbase.filter.WhileMatchFilter}.
+ * The latter returns as soon as the filter stops matching.
+ * </p>
+ * <p>Do not rely on filters carrying state across rows; its not reliable in current
+ * hbase as we have no handlers in place for when regions split, close or server
+ * crashes.
+ */
 package org.apache.hadoop.hbase.filter;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/AbstractRpcClient.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/AbstractRpcClient.java
index 7c0149ccb8a3..9d557a98743c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/AbstractRpcClient.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/AbstractRpcClient.java
@@ -238,7 +238,8 @@ Codec getCodec() {
       return null;
     }
     try {
-      return (Codec) Class.forName(className).getDeclaredConstructor().newInstance();
+      return Class.forName(className).asSubclass(Codec.class).getDeclaredConstructor()
+        .newInstance();
     } catch (Exception e) {
       throw new RuntimeException("Failed getting codec " + className, e);
     }
@@ -265,7 +266,8 @@ private static CompressionCodec getCompressor(final Configuration conf) {
       return null;
     }
     try {
-      return (CompressionCodec) Class.forName(className).getDeclaredConstructor().newInstance();
+      return Class.forName(className).asSubclass(CompressionCodec.class).getDeclaredConstructor()
+        .newInstance();
     } catch (Exception e) {
       throw new RuntimeException("Failed getting compressor " + className, e);
     }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/BlockingRpcConnection.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/BlockingRpcConnection.java
index c8adc6a8cc3c..da032cbeb9d1 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/BlockingRpcConnection.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/BlockingRpcConnection.java
@@ -67,7 +67,6 @@
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.protobuf.Message;
-import org.apache.hbase.thirdparty.com.google.protobuf.Message.Builder;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcCallback;
 import org.apache.hbase.thirdparty.io.netty.buffer.ByteBuf;
 import org.apache.hbase.thirdparty.io.netty.buffer.PooledByteBufAllocator;
@@ -181,6 +180,8 @@ public void run() {
             try {
               BlockingRpcConnection.this.wait();
             } catch (InterruptedException e) {
+              // Restore interrupt status
+              Thread.currentThread().interrupt();
             }
             // check if we need to quit, so continue the main loop instead of fallback.
             continue;
@@ -333,6 +334,8 @@ private synchronized boolean waitForWork() {
       try {
         wait(Math.min(this.rpcClient.minIdleTimeBeforeClose, 1000));
       } catch (InterruptedException e) {
+        // Restore interrupt status
+        Thread.currentThread().interrupt();
       }
     }
   }
@@ -685,7 +688,7 @@ private void readResponse() {
       } else {
         Message value = null;
         if (call.responseDefaultType != null) {
-          Builder builder = call.responseDefaultType.newBuilderForType();
+          Message.Builder builder = call.responseDefaultType.newBuilderForType();
           ProtobufUtil.mergeDelimitedFrom(builder, in);
           value = builder.build();
         }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/CellBlockBuilder.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/CellBlockBuilder.java
index 9e9c0688ecee..b2b3698aa2cb 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/CellBlockBuilder.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/CellBlockBuilder.java
@@ -228,6 +228,7 @@ public ByteBufferListOutputStream buildCellBlockStream(Codec codec, CompressionC
   }
 
   /**
+   * Create a cell scanner.
    * @param codec     to use for cellblock
    * @param cellBlock to encode
    * @return CellScanner to work against the content of <code>cellBlock</code>
@@ -248,6 +249,7 @@ public CellScanner createCellScanner(final Codec codec, final CompressionCodec c
   }
 
   /**
+   * Create a cell scanner using an existing bytebuff.
    * @param codec     to use for cellblock
    * @param cellBlock ByteBuffer containing the cells written by the Codec. The buffer should be
    *                  position()'ed at the start of the cell block and limit()'ed at the end.
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/ConnectionId.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/ConnectionId.java
index 6cb9cddd9feb..4de82e0c12af 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/ConnectionId.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/ConnectionId.java
@@ -57,14 +57,18 @@ public String toString() {
   }
 
   @Override
+  @SuppressWarnings("ReferenceEquality")
   public boolean equals(Object obj) {
-    if (obj instanceof ConnectionId) {
-      ConnectionId id = (ConnectionId) obj;
-      return address.equals(id.address)
-        && ((ticket != null && ticket.equals(id.ticket)) || (ticket == id.ticket))
-        && Objects.equals(this.serviceName, id.serviceName);
+    if (obj == this) {
+      return true;
     }
-    return false;
+    if (!(obj instanceof ConnectionId)) {
+      return false;
+    }
+    ConnectionId id = (ConnectionId) obj;
+    return address.equals(id.address)
+      && ((ticket != null && ticket.equals(id.ticket)) || (ticket == id.ticket))
+      && Objects.equals(this.serviceName, id.serviceName);
   }
 
   @Override // simply use the default Object#hashcode() ?
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/HBaseRpcController.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/HBaseRpcController.java
index 01412631ef7d..c60de7658f3d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/HBaseRpcController.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/HBaseRpcController.java
@@ -50,12 +50,14 @@ public interface HBaseRpcController extends RpcController, CellScannable {
   void setCellScanner(CellScanner cellScanner);
 
   /**
+   * Set the priority for this operation.
    * @param priority Priority for this request; should fall roughly in the range
    *                 {@link HConstants#NORMAL_QOS} to {@link HConstants#HIGH_QOS}
    */
   void setPriority(int priority);
 
   /**
+   * Set the priority for this operation.
    * @param tn Set priority based off the table we are going against.
    */
   void setPriority(final TableName tn);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/NettyRpcDuplexHandler.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/NettyRpcDuplexHandler.java
index fe32189f81bd..700093a30274 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/NettyRpcDuplexHandler.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/NettyRpcDuplexHandler.java
@@ -31,7 +31,6 @@
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.protobuf.Message;
-import org.apache.hbase.thirdparty.com.google.protobuf.Message.Builder;
 import org.apache.hbase.thirdparty.com.google.protobuf.TextFormat;
 import org.apache.hbase.thirdparty.io.netty.buffer.ByteBuf;
 import org.apache.hbase.thirdparty.io.netty.buffer.ByteBufInputStream;
@@ -168,7 +167,7 @@ private void readResponse(ChannelHandlerContext ctx, ByteBuf buf) throws IOExcep
     }
     Message value;
     if (call.responseDefaultType != null) {
-      Builder builder = call.responseDefaultType.newBuilderForType();
+      Message.Builder builder = call.responseDefaultType.newBuilderForType();
       builder.mergeDelimitedFrom(in);
       value = builder.build();
     } else {
@@ -202,7 +201,7 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
     }
   }
 
-  private void cleanupCalls(ChannelHandlerContext ctx, IOException error) {
+  private void cleanupCalls(IOException error) {
     for (Call call : id2Call.values()) {
       call.setException(error);
     }
@@ -212,7 +211,7 @@ private void cleanupCalls(ChannelHandlerContext ctx, IOException error) {
   @Override
   public void channelInactive(ChannelHandlerContext ctx) throws Exception {
     if (!id2Call.isEmpty()) {
-      cleanupCalls(ctx, new ConnectionClosedException("Connection closed"));
+      cleanupCalls(new ConnectionClosedException("Connection closed"));
     }
     conn.shutdown();
     ctx.fireChannelInactive();
@@ -221,7 +220,7 @@ public void channelInactive(ChannelHandlerContext ctx) throws Exception {
   @Override
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
     if (!id2Call.isEmpty()) {
-      cleanupCalls(ctx, IPCUtil.toIOE(cause));
+      cleanupCalls(IPCUtil.toIOE(cause));
     }
     conn.shutdown();
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcClient.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcClient.java
index 6ecff49e52b1..045216e88811 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcClient.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcClient.java
@@ -90,8 +90,8 @@ public interface RpcClient extends Closeable {
   void close();
 
   /**
-   * @return true when this client uses a {@link org.apache.hadoop.hbase.codec.Codec} and so
-   *         supports cell blocks.
+   * Return true when this client uses a {@link org.apache.hadoop.hbase.codec.Codec} and so supports
+   * cell blocks.
    */
   boolean hasCellBlockSupport();
 }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java
index 2b0f2f4509e4..a78ece64d7fe 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/master/RegionState.java
@@ -417,12 +417,13 @@ public static RegionState convert(ClusterStatusProtos.RegionState proto) {
    */
   @Override
   public boolean equals(Object obj) {
-    if (this == obj) return true;
-    if (obj == null || getClass() != obj.getClass()) {
+    if (this == obj) {
+      return true;
+    }
+    if (!(obj instanceof RegionState)) {
       return false;
     }
     RegionState tmp = (RegionState) obj;
-
     return RegionInfo.COMPARATOR.compare(tmp.hri, hri) == 0 && tmp.state == state
       && ((serverName != null && serverName.equals(tmp.serverName))
         || (tmp.serverName == null && serverName == null));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/ProtobufMagic.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/ProtobufMagic.java
index 15a196cbe5b5..4a285ba40be3 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/ProtobufMagic.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/protobuf/ProtobufMagic.java
@@ -35,8 +35,7 @@ private ProtobufMagic() {
   public static final byte[] PB_MAGIC = new byte[] { 'P', 'B', 'U', 'F' };
 
   /**
-   * @param bytes Bytes to check.
-   * @return True if passed <code>bytes</code> has {@link #PB_MAGIC} for a prefix.
+   * Returns True if passed <code>bytes</code> has {@link #PB_MAGIC} for a prefix.
    */
   public static boolean isPBMagicPrefix(final byte[] bytes) {
     if (bytes == null) return false;
@@ -66,12 +65,7 @@ private static int compareTo(byte[] buffer1, int offset1, int length1, byte[] bu
     return length1 - length2;
   }
 
-  /**
-   * @param bytes  Bytes to check.
-   * @param offset offset to start at
-   * @param len    length to use
-   * @return True if passed <code>bytes</code> has {@link #PB_MAGIC} for a prefix.
-   */
+  /** Returns True if passed <code>bytes</code> has {@link #PB_MAGIC} for a prefix. */
   public static boolean isPBMagicPrefix(final byte[] bytes, int offset, int len) {
     if (bytes == null || len < PB_MAGIC.length) return false;
     return compareTo(PB_MAGIC, 0, PB_MAGIC.length, bytes, offset, PB_MAGIC.length) == 0;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaRetriever.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaRetriever.java
index 728959e0a0ca..1dd5bf275bba 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaRetriever.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaRetriever.java
@@ -19,8 +19,8 @@
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.ArrayDeque;
 import java.util.Iterator;
-import java.util.LinkedList;
 import java.util.Objects;
 import java.util.Queue;
 import org.apache.hadoop.conf.Configuration;
@@ -43,7 +43,7 @@
 public class QuotaRetriever implements Closeable, Iterable<QuotaSettings> {
   private static final Logger LOG = LoggerFactory.getLogger(QuotaRetriever.class);
 
-  private final Queue<QuotaSettings> cache = new LinkedList<>();
+  private final Queue<QuotaSettings> cache = new ArrayDeque<>();
   private ResultScanner scanner;
   /**
    * Connection to use. Could pass one in and have this class use it but this class wants to be
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/SpaceLimitSettings.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/SpaceLimitSettings.java
index 878cbe871e57..4a2303385987 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/SpaceLimitSettings.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/SpaceLimitSettings.java
@@ -23,7 +23,7 @@
 import org.apache.yetus.audience.InterfaceStability;
 
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
-import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.SetQuotaRequest.Builder;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.SetQuotaRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos.SpaceLimitRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos.SpaceQuota;
@@ -113,7 +113,7 @@ public QuotaType getQuotaType() {
   }
 
   @Override
-  protected void setupSetQuotaRequest(Builder builder) {
+  protected void setupSetQuotaRequest(SetQuotaRequest.Builder builder) {
     // TableName/Namespace are serialized in QuotaSettings
     builder.setSpaceLimit(proto);
   }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
index c2dc1042c913..122ad8db82fb 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
@@ -29,6 +29,8 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+
 @InterfaceAudience.Private
 public class SaslUtil {
   private static final Logger LOG = LoggerFactory.getLogger(SaslUtil.class);
@@ -93,6 +95,7 @@ public static QualityOfProtection getQop(String stringQop) {
   }
 
   /**
+   * Initialize SASL properties for a given RPC protection level.
    * @param rpcProtection Value of 'hbase.rpc.protection' configuration.
    * @return Map with values for SASL properties.
    */
@@ -101,10 +104,9 @@ public static Map<String, String> initSaslProperties(String rpcProtection) {
     if (rpcProtection.isEmpty()) {
       saslQop = QualityOfProtection.AUTHENTICATION.getSaslQop();
     } else {
-      String[] qops = rpcProtection.split(",");
       StringBuilder saslQopBuilder = new StringBuilder();
-      for (int i = 0; i < qops.length; ++i) {
-        QualityOfProtection qop = getQop(qops[i]);
+      for (String s : Splitter.on(',').splitToList(rpcProtection)) {
+        QualityOfProtection qop = getQop(s);
         saslQopBuilder.append(",").append(qop.getSaslQop());
       }
       saslQop = saslQopBuilder.substring(1); // remove first ','
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlClient.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlClient.java
index b6986b564ac8..e30041d46c48 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlClient.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlClient.java
@@ -29,16 +29,11 @@
 import org.apache.hadoop.hbase.ZooKeeperConnectionException;
 import org.apache.hadoop.hbase.client.Admin;
 import org.apache.hadoop.hbase.client.Connection;
-import org.apache.hadoop.hbase.client.Table;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.security.SecurityCapability;
-import org.apache.hadoop.hbase.ipc.CoprocessorRpcChannel;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.yetus.audience.InterfaceAudience;
 
-import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos;
-import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.AccessControlService.BlockingInterface;
-
 /**
  * Utility client for doing access control admin operations.
  */
@@ -67,17 +62,17 @@ public static boolean isCellAuthorizationEnabled(Connection connection) throws I
       .contains(SecurityCapability.CELL_AUTHORIZATION);
   }
 
-  private static BlockingInterface getAccessControlServiceStub(Table ht) throws IOException {
-    CoprocessorRpcChannel service = ht.coprocessorService(HConstants.EMPTY_START_ROW);
-    BlockingInterface protocol = AccessControlProtos.AccessControlService.newBlockingStub(service);
-    return protocol;
-  }
-
   /**
    * Grants permission on the specified table for the specified user
-   * @param connection The Connection instance to use nnnn * @param mergeExistingPermissions If set
-   *                   to false, later granted permissions will override previous granted
-   *                   permissions. otherwise, it'll merge with previous granted permissions. nn
+   * @param connection               The Connection instance to use
+   * @param tableName                the table name
+   * @param userName                 the user name
+   * @param family                   the column family
+   * @param qual                     the column qualifier
+   * @param mergeExistingPermissions If set to false, later granted permissions will override
+   *                                 previous granted permissions. otherwise, it'll merge with
+   *                                 previous granted permissions.
+   * @param actions                  the actions
    */
   private static void grant(Connection connection, final TableName tableName, final String userName,
     final byte[] family, final byte[] qual, boolean mergeExistingPermissions,
@@ -90,7 +85,12 @@ private static void grant(Connection connection, final TableName tableName, fina
   /**
    * Grants permission on the specified table for the specified user. If permissions for a specified
    * user exists, later granted permissions will override previous granted permissions.
-   * @param connection The Connection instance to use nnnnnn
+   * @param connection The Connection instance to use
+   * @param tableName  the table name
+   * @param userName   the user name
+   * @param family     the column family
+   * @param qual       the column qualifier
+   * @param actions    the actions
    */
   public static void grant(Connection connection, final TableName tableName, final String userName,
     final byte[] family, final byte[] qual, final Permission.Action... actions) throws Throwable {
@@ -98,9 +98,14 @@ public static void grant(Connection connection, final TableName tableName, final
   }
 
   /**
-   * Grants permission on the specified namespace for the specified user. nnn * @param
-   * mergeExistingPermissions If set to false, later granted permissions will override previous
-   * granted permissions. otherwise, it'll merge with previous granted permissions. nn
+   * Grants permission on the specified namespace for the specified user.
+   * @param connection               The Connection instance to use
+   * @param namespace                the namespace
+   * @param userName                 the user name
+   * @param mergeExistingPermissions If set to false, later granted permissions will override
+   *                                 previous granted permissions. otherwise, it'll merge with
+   *                                 previous granted permissions.
+   * @param actions                  the actions
    */
   private static void grant(Connection connection, final String namespace, final String userName,
     boolean mergeExistingPermissions, final Permission.Action... actions) throws Throwable {
@@ -113,7 +118,10 @@ private static void grant(Connection connection, final String namespace, final S
    * Grants permission on the specified namespace for the specified user. If permissions on the
    * specified namespace exists, later granted permissions will override previous granted
    * permissions.
-   * @param connection The Connection instance to use nnnn
+   * @param connection The Connection instance to use
+   * @param namespace  the namespace
+   * @param userName   the user name
+   * @param actions    the actions
    */
   public static void grant(Connection connection, final String namespace, final String userName,
     final Permission.Action... actions) throws Throwable {
@@ -121,9 +129,13 @@ public static void grant(Connection connection, final String namespace, final St
   }
 
   /**
-   * Grant global permissions for the specified user. nn * @param mergeExistingPermissions If set to
-   * false, later granted permissions will override previous granted permissions. otherwise, it'll
-   * merge with previous granted permissions. nn
+   * Grant global permissions for the specified user.
+   * @param connection               The Connection instance to use
+   * @param userName                 the user name
+   * @param mergeExistingPermissions If set to false, later granted permissions will override
+   *                                 previous granted permissions. otherwise, it'll merge with
+   *                                 previous granted permissions.
+   * @param actions                  the actions
    */
   private static void grant(Connection connection, final String userName,
     boolean mergeExistingPermissions, final Permission.Action... actions) throws Throwable {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlUtil.java
index 066e6f4e04da..e0eb79aa0257 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/AccessControlUtil.java
@@ -42,9 +42,6 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.AccessControlService;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.GetUserPermissionsResponse;
 
-/**
- * @since 2.0.0
- */
 @InterfaceAudience.Private
 public class AccessControlUtil {
   private AccessControlUtil() {
@@ -226,13 +223,12 @@ public static AccessControlProtos.UsersAndPermissions toUsersAndPermissions(Stri
    */
   public static TablePermission toTablePermission(AccessControlProtos.TablePermission proto) {
     Permission.Action[] actions = toPermissionActions(proto.getActionList());
-    TableName table = null;
-    byte[] qualifier = null;
-    byte[] family = null;
     if (!proto.hasTableName()) {
       throw new IllegalStateException("TableName cannot be empty");
     }
-    table = ProtobufUtil.toTableName(proto.getTableName());
+    TableName table = ProtobufUtil.toTableName(proto.getTableName());
+    byte[] family = null;
+    byte[] qualifier = null;
     if (proto.hasFamily()) {
       family = proto.getFamily().toByteArray();
     }
@@ -265,13 +261,12 @@ public static Permission toPermission(AccessControlProtos.Permission proto) {
     if (proto.getType() == AccessControlProtos.Permission.Type.Table) {
       AccessControlProtos.TablePermission perm = proto.getTablePermission();
       Permission.Action[] actions = toPermissionActions(perm.getActionList());
-      byte[] qualifier = null;
-      byte[] family = null;
-      TableName table = null;
       if (!perm.hasTableName()) {
         throw new IllegalStateException("TableName cannot be empty");
       }
-      table = ProtobufUtil.toTableName(perm.getTableName());
+      TableName table = ProtobufUtil.toTableName(perm.getTableName());
+      byte[] family = null;
+      byte[] qualifier = null;
       if (perm.hasFamily()) {
         family = perm.getFamily().toByteArray();
       }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/ShadedAccessControlUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/ShadedAccessControlUtil.java
index b6df2c94a044..cf7c797c98ac 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/ShadedAccessControlUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/ShadedAccessControlUtil.java
@@ -21,7 +21,6 @@
 import java.util.List;
 import java.util.Map;
 import org.apache.hadoop.hbase.TableName;
-import org.apache.hadoop.hbase.security.access.Permission.Action;
 import org.apache.yetus.audience.InterfaceAudience;
 
 import org.apache.hbase.thirdparty.com.google.common.collect.ArrayListMultimap;
@@ -32,7 +31,6 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.GetUserPermissionsResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.GrantRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.HasUserPermissionsRequest;
-import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.Permission.Type;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos.RevokeRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 
@@ -122,12 +120,12 @@ public static Permission toPermission(AccessControlProtos.Permission proto) {
 
     if (proto.getType() == AccessControlProtos.Permission.Type.Global) {
       AccessControlProtos.GlobalPermission perm = proto.getGlobalPermission();
-      Action[] actions = toPermissionActions(perm.getActionList());
+      Permission.Action[] actions = toPermissionActions(perm.getActionList());
       return Permission.newBuilder().withActions(actions).build();
     }
     if (proto.getType() == AccessControlProtos.Permission.Type.Namespace) {
       AccessControlProtos.NamespacePermission perm = proto.getNamespacePermission();
-      Action[] actions = toPermissionActions(perm.getActionList());
+      Permission.Action[] actions = toPermissionActions(perm.getActionList());
 
       if (!proto.hasNamespacePermission()) {
         throw new IllegalStateException("Namespace must not be empty in NamespacePermission");
@@ -137,7 +135,7 @@ public static Permission toPermission(AccessControlProtos.Permission proto) {
     }
     if (proto.getType() == AccessControlProtos.Permission.Type.Table) {
       AccessControlProtos.TablePermission perm = proto.getTablePermission();
-      Action[] actions = toPermissionActions(perm.getActionList());
+      Permission.Action[] actions = toPermissionActions(perm.getActionList());
 
       byte[] qualifier = null;
       byte[] family = null;
@@ -292,14 +290,14 @@ public static RevokeRequest buildRevokeRequest(UserPermission userPermission) {
     }
     if (request.getNamespace() != null && !request.getNamespace().isEmpty()) {
       builder.setNamespaceName(ByteString.copyFromUtf8(request.getNamespace()));
-      builder.setType(Type.Namespace);
+      builder.setType(AccessControlProtos.Permission.Type.Namespace);
     }
     if (request.getTableName() != null) {
       builder.setTableName(toProtoTableName(request.getTableName()));
-      builder.setType(Type.Table);
+      builder.setType(AccessControlProtos.Permission.Type.Table);
     }
     if (!builder.hasType()) {
-      builder.setType(Type.Global);
+      builder.setType(AccessControlProtos.Permission.Type.Global);
     }
     if (request.getFamily() != null && request.getFamily().length > 0) {
       builder.setColumnFamily(ByteString.copyFrom(request.getFamily()));
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/TablePermission.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/TablePermission.java
index e0a12c7d431f..65ebbef7da09 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/TablePermission.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/access/TablePermission.java
@@ -141,11 +141,11 @@ public boolean implies(TableName table, KeyValue kv, Action action) {
       return false;
     }
 
-    if (family != null && !(CellUtil.matchingFamily(kv, family))) {
+    if (family != null && !CellUtil.matchingFamily(kv, family)) {
       return false;
     }
 
-    if (qualifier != null && !(CellUtil.matchingQualifier(kv, qualifier))) {
+    if (qualifier != null && !CellUtil.matchingQualifier(kv, qualifier)) {
       return false;
     }
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
index e9990066050e..eb91edb3e801 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
@@ -48,6 +48,7 @@ public final int hashCode() {
   }
 
   @Override
+  @SuppressWarnings("EqualsUsingHashCode")
   public final boolean equals(Object o) {
     // SaslClientAuthProviders should be unique via their hashCode().
     if (o instanceof AbstractSaslClientAuthenticationProvider) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityClient.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityClient.java
index 42508782d1a7..7bae98d59bab 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityClient.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityClient.java
@@ -88,7 +88,7 @@ public VisibilityLabelsResponse call(VisibilityLabelsService service) throws IOE
             for (String label : labels) {
               if (label.length() > 0) {
                 VisibilityLabel.Builder newBuilder = VisibilityLabel.newBuilder();
-                newBuilder.setLabel(UnsafeByteOperations.unsafeWrap((Bytes.toBytes(label))));
+                newBuilder.setLabel(UnsafeByteOperations.unsafeWrap(Bytes.toBytes(label)));
                 builder.addVisLabel(newBuilder.build());
               }
             }
@@ -117,8 +117,10 @@ public static VisibilityLabelsResponse setAuths(Connection connection, final Str
   }
 
   /**
-   * @param connection the Connection instance to use. n * @return labels, the given user is
-   *                   globally authorized for. n
+   * Get the authorization for a given user
+   * @param connection the Connection instance to use
+   * @param user       the user
+   * @return labels the given user is globally authorized for
    */
   public static GetAuthsResponse getAuths(Connection connection, final String user)
     throws Throwable {
@@ -212,7 +214,7 @@ public VisibilityLabelsResponse call(VisibilityLabelsService service) throws IOE
             setAuthReqBuilder.setUser(UnsafeByteOperations.unsafeWrap(Bytes.toBytes(user)));
             for (String auth : auths) {
               if (auth.length() > 0) {
-                setAuthReqBuilder.addAuth((ByteString.copyFromUtf8(auth)));
+                setAuthReqBuilder.addAuth(ByteString.copyFromUtf8(auth));
               }
             }
             if (setOrClear) {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
index 27bc29702f89..35c361be5629 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
@@ -51,7 +51,6 @@
 import org.apache.hadoop.hbase.CacheEvictionStats;
 import org.apache.hadoop.hbase.CacheEvictionStatsBuilder;
 import org.apache.hadoop.hbase.Cell;
-import org.apache.hadoop.hbase.Cell.Type;
 import org.apache.hadoop.hbase.CellBuilderType;
 import org.apache.hadoop.hbase.CellScanner;
 import org.apache.hadoop.hbase.CellUtil;
@@ -309,25 +308,18 @@ public static byte[] prependPBMagic(final byte[] bytes) {
     return Bytes.add(PB_MAGIC, bytes);
   }
 
-  /**
-   * @param bytes Bytes to check.
-   * @return True if passed <code>bytes</code> has {@link ProtobufMagic#PB_MAGIC} for a prefix.
-   */
+  /** Returns True if passed <code>bytes</code> has {@link ProtobufMagic#PB_MAGIC} for a prefix. */
   public static boolean isPBMagicPrefix(final byte[] bytes) {
     return ProtobufMagic.isPBMagicPrefix(bytes);
   }
 
-  /**
-   * @param bytes  Bytes to check.
-   * @param offset offset to start at
-   * @param len    length to use
-   * @return True if passed <code>bytes</code> has {@link ProtobufMagic#PB_MAGIC} for a prefix.
-   */
+  /** Returns True if passed <code>bytes</code> has {@link ProtobufMagic#PB_MAGIC} for a prefix. */
   public static boolean isPBMagicPrefix(final byte[] bytes, int offset, int len) {
     return ProtobufMagic.isPBMagicPrefix(bytes, offset, len);
   }
 
   /**
+   * Expect the {@link ProtobufMagic#PB_MAGIC} or throw an exception.
    * @param bytes bytes to check
    * @throws DeserializationException if we are missing the pb magic prefix
    */
@@ -732,7 +724,7 @@ public static Put toPut(final MutationProto proto, final CellScanner cellScanner
             } else {
               put.add(cellBuilder.clear().setRow(put.getRow()).setFamily(family)
                 .setQualifier(qv.hasQualifier() ? qv.getQualifier().toByteArray() : null)
-                .setTimestamp(ts).setType(Type.Put)
+                .setTimestamp(ts).setType(Cell.Type.Put)
                 .setValue(qv.hasValue() ? qv.getValue().toByteArray() : null).build());
             }
           }
@@ -889,9 +881,9 @@ private static long cellTimestampOrLatest(QualifierValue cell) {
   }
 
   /**
-   * Convert a protocol buffer Mutate to an Append n * @param proto the protocol buffer Mutate to
-   * convert
-   * @return the converted client Append n
+   * Convert a protocol buffer Mutate to an Append
+   * @param proto the protocol buffer Mutate to convert
+   * @return the converted client Append
    */
   public static Append toAppend(final MutationProto proto, final CellScanner cellScanner)
     throws IOException {
@@ -909,7 +901,7 @@ public static Append toAppend(final MutationProto proto, final CellScanner cellS
   /**
    * Convert a protocol buffer Mutate to an Increment
    * @param proto the protocol buffer Mutate to convert
-   * @return the converted client Increment n
+   * @return the converted client Increment
    */
   public static Increment toIncrement(final MutationProto proto, final CellScanner cellScanner)
     throws IOException {
@@ -1678,7 +1670,6 @@ public static org.apache.hadoop.hbase.client.RegionInfo getRegionInfo(
     final RpcController controller, final AdminService.BlockingInterface admin,
     final byte[] regionName) throws IOException {
     try {
-      GetRegionInfoRequest request = getGetRegionInfoRequest(regionName);
       GetRegionInfoResponse response =
         admin.getRegionInfo(controller, getGetRegionInfoRequest(regionName));
       return toRegionInfo(response.getRegionInfo());
@@ -1840,9 +1831,6 @@ public static long getTotalRequestsCount(RegionLoad rl) {
     return rl.getReadRequestsCount() + rl.getWriteRequestsCount();
   }
 
-  /**
-   * @param m Message to get delimited pb serialization of (with pb magic prefix)
-   */
   public static byte[] toDelimitedByteArray(final Message m) throws IOException {
     // Allocate arbitrary big size so we avoid resizing.
     ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
index 79efe9c8fa18..13e85f91c958 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
@@ -704,6 +704,7 @@ public static GetRegionInfoRequest buildGetRegionInfoRequest(final byte[] region
   }
 
   /**
+   * Create a protocol buffer GetRegionInfoRequest,
    * @param regionName             the name of the region to get info
    * @param includeCompactionState indicate if the compaction state is requested
    * @param includeBestSplitRow    indicate if the bestSplitRow is requested
@@ -912,7 +913,7 @@ public static AddColumnRequest buildAddColumnRequest(final TableName tableName,
   public static DeleteColumnRequest buildDeleteColumnRequest(final TableName tableName,
     final byte[] columnName, final long nonceGroup, final long nonce) {
     DeleteColumnRequest.Builder builder = DeleteColumnRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setColumnName(UnsafeByteOperations.unsafeWrap(columnName));
     builder.setNonceGroup(nonceGroup);
     builder.setNonce(nonce);
@@ -925,7 +926,7 @@ public static DeleteColumnRequest buildDeleteColumnRequest(final TableName table
   public static ModifyColumnRequest buildModifyColumnRequest(final TableName tableName,
     final ColumnFamilyDescriptor column, final long nonceGroup, final long nonce) {
     ModifyColumnRequest.Builder builder = ModifyColumnRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setColumnFamilies(ProtobufUtil.toColumnFamilySchema(column));
     builder.setNonceGroup(nonceGroup);
     builder.setNonce(nonce);
@@ -937,7 +938,7 @@ public static ModifyColumnStoreFileTrackerRequest buildModifyColumnStoreFileTrac
     final long nonce) {
     ModifyColumnStoreFileTrackerRequest.Builder builder =
       ModifyColumnStoreFileTrackerRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setFamily(ByteString.copyFrom(family));
     builder.setDstSft(dstSFT);
     builder.setNonceGroup(nonceGroup);
@@ -1059,7 +1060,7 @@ public static EnableTableRequest buildEnableTableRequest(final TableName tableNa
   public static DisableTableRequest buildDisableTableRequest(final TableName tableName,
     final long nonceGroup, final long nonce) {
     DisableTableRequest.Builder builder = DisableTableRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setNonceGroup(nonceGroup);
     builder.setNonce(nonce);
     return builder.build();
@@ -1088,7 +1089,7 @@ public static CreateTableRequest buildCreateTableRequest(final TableDescriptor t
   public static ModifyTableRequest buildModifyTableRequest(final TableName tableName,
     final TableDescriptor tableDesc, final long nonceGroup, final long nonce) {
     ModifyTableRequest.Builder builder = ModifyTableRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setTableSchema(ProtobufUtil.toTableSchema(tableDesc));
     builder.setNonceGroup(nonceGroup);
     builder.setNonce(nonce);
@@ -1099,7 +1100,7 @@ public static ModifyTableStoreFileTrackerRequest buildModifyTableStoreFileTracke
     final TableName tableName, final String dstSFT, final long nonceGroup, final long nonce) {
     ModifyTableStoreFileTrackerRequest.Builder builder =
       ModifyTableStoreFileTrackerRequest.newBuilder();
-    builder.setTableName(ProtobufUtil.toProtoTableName((tableName)));
+    builder.setTableName(ProtobufUtil.toProtoTableName(tableName));
     builder.setDstSft(dstSFT);
     builder.setNonceGroup(nonceGroup);
     builder.setNonce(nonce);
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/util/Writables.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/util/Writables.java
index 7ebbbf44cebd..091515c325ed 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/util/Writables.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/util/Writables.java
@@ -34,6 +34,7 @@
 @InterfaceAudience.Private
 public class Writables {
   /**
+   * Get the Writable's contents as a byte array
    * @param w writable
    * @return The bytes of <code>w</code> gotten by running its
    *         {@link Writable#write(java.io.DataOutput)} method.
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.java
index 96170736208b..979094fda80b 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ReadOnlyZKClient.java
@@ -183,6 +183,8 @@ public void exec(ZooKeeper alwaysNull) {
               try {
                 zk.close();
               } catch (InterruptedException e) {
+                // Restore interrupt status
+                Thread.currentThread().interrupt();
               }
             }
             if (ZKTask.this.delay(retryIntervalMs, maxRetries)) {
@@ -303,6 +305,8 @@ private void closeZk() {
       try {
         zookeeper.close();
       } catch (InterruptedException e) {
+        // Restore interrupt status
+        Thread.currentThread().interrupt();
       }
       zookeeper = null;
     }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKMetadata.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKMetadata.java
index f0fae958a66a..b795ad45aa1c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKMetadata.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKMetadata.java
@@ -54,7 +54,7 @@ public static byte[] appendMetaData(byte[] id, byte[] data) {
     pos = Bytes.putInt(newData, pos, idLength);
     pos = Bytes.putBytes(newData, pos, id, 0, id.length);
     pos = Bytes.putBytes(newData, pos, salt, 0, salt.length);
-    pos = Bytes.putBytes(newData, pos, data, 0, data.length);
+    Bytes.putBytes(newData, pos, data, 0, data.length);
     return newData;
   }
 
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableRpcPriority.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableRpcPriority.java
index db3ccebe89d2..e57967ae7211 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableRpcPriority.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableRpcPriority.java
@@ -45,7 +45,6 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.Cell;
-import org.apache.hadoop.hbase.Cell.Type;
 import org.apache.hadoop.hbase.CellBuilderFactory;
 import org.apache.hadoop.hbase.CellBuilderType;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
@@ -135,10 +134,11 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
           case INCREMENT:
             ColumnValue value = req.getColumnValue(0);
             QualifierValue qvalue = value.getQualifierValue(0);
-            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Type.Put)
-              .setRow(req.getRow().toByteArray()).setFamily(value.getFamily().toByteArray())
-              .setQualifier(qvalue.getQualifier().toByteArray())
-              .setValue(qvalue.getValue().toByteArray()).build();
+            Cell cell =
+              CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Cell.Type.Put)
+                .setRow(req.getRow().toByteArray()).setFamily(value.getFamily().toByteArray())
+                .setQualifier(qvalue.getQualifier().toByteArray())
+                .setValue(qvalue.getValue().toByteArray()).build();
             resp = MutateResponse.newBuilder()
               .setResult(ProtobufUtil.toResult(Result.create(Arrays.asList(cell)))).build();
             break;
@@ -496,8 +496,8 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
             assertFalse("close scanner should not come in with scan priority " + scanPriority,
               req.hasCloseScanner() && req.getCloseScanner());
 
-            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Type.Put)
-              .setRow(Bytes.toBytes(scanNextCalled.incrementAndGet()))
+            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY)
+              .setType(Cell.Type.Put).setRow(Bytes.toBytes(scanNextCalled.incrementAndGet()))
               .setFamily(Bytes.toBytes("cf")).setQualifier(Bytes.toBytes("cq"))
               .setValue(Bytes.toBytes("v")).build();
             Result result = Result.create(Arrays.asList(cell));
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableTracing.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableTracing.java
index 99e52361109c..f9b86221af1e 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableTracing.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableTracing.java
@@ -54,7 +54,6 @@
 import java.util.stream.Collectors;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.Cell;
-import org.apache.hadoop.hbase.Cell.Type;
 import org.apache.hadoop.hbase.CellBuilderFactory;
 import org.apache.hadoop.hbase.CellBuilderType;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
@@ -135,8 +134,8 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
           if (req.hasCloseScanner() && req.getCloseScanner()) {
             done.run(ScanResponse.getDefaultInstance());
           } else {
-            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Type.Put)
-              .setRow(Bytes.toBytes(scanNextCalled.incrementAndGet()))
+            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY)
+              .setType(Cell.Type.Put).setRow(Bytes.toBytes(scanNextCalled.incrementAndGet()))
               .setFamily(Bytes.toBytes("cf")).setQualifier(Bytes.toBytes("cq"))
               .setValue(Bytes.toBytes("v")).build();
             Result result = Result.create(Arrays.asList(cell));
@@ -183,10 +182,11 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
           case INCREMENT:
             ColumnValue value = req.getColumnValue(0);
             QualifierValue qvalue = value.getQualifierValue(0);
-            Cell cell = CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Type.Put)
-              .setRow(req.getRow().toByteArray()).setFamily(value.getFamily().toByteArray())
-              .setQualifier(qvalue.getQualifier().toByteArray())
-              .setValue(qvalue.getValue().toByteArray()).build();
+            Cell cell =
+              CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setType(Cell.Type.Put)
+                .setRow(req.getRow().toByteArray()).setFamily(value.getFamily().toByteArray())
+                .setQualifier(qvalue.getQualifier().toByteArray())
+                .setValue(qvalue.getValue().toByteArray()).build();
             resp = MutateResponse.newBuilder()
               .setResult(ProtobufUtil.toResult(Result.create(Arrays.asList(cell)))).build();
             break;
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestCoprocessorDescriptor.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestCoprocessorDescriptor.java
index f1a8e000136d..a56c863ce614 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestCoprocessorDescriptor.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestCoprocessorDescriptor.java
@@ -33,8 +33,6 @@
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.rules.TestName;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Category({ MiscTests.class, SmallTests.class })
 public class TestCoprocessorDescriptor {
@@ -43,8 +41,6 @@ public class TestCoprocessorDescriptor {
   public static final HBaseClassTestRule CLASS_RULE =
     HBaseClassTestRule.forClass(TestCoprocessorDescriptor.class);
 
-  private static final Logger LOG = LoggerFactory.getLogger(TestCoprocessorDescriptor.class);
-
   @Rule
   public TestName name = new TestName();
 
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestGet.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestGet.java
index 44a1c577b10d..69c33c833b0c 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestGet.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestGet.java
@@ -250,8 +250,7 @@ public void testDynamicFilter() throws Exception {
   public void testGetRowConstructor() {
     byte[] row1 = Bytes.toBytes("testRow");
     byte[] row2 = Bytes.toBytes("testtestRow");
-    ByteBuffer rowBuffer = ByteBuffer.allocate(16);
-    rowBuffer = ByteBuffer.wrap(row1);
+    ByteBuffer rowBuffer = ByteBuffer.wrap(row1);
     Get get1 = new Get(rowBuffer);
     Get get2 = new Get(row2, 4, 7);
     Assert.assertArrayEquals(get1.getRow(), get2.getRow());
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestMutation.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestMutation.java
index dcb4d6eb88ad..718ca05b92f3 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestMutation.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestMutation.java
@@ -23,7 +23,6 @@
 import java.io.IOException;
 import java.util.List;
 import org.apache.hadoop.hbase.Cell;
-import org.apache.hadoop.hbase.Cell.Type;
 import org.apache.hadoop.hbase.CellBuilderFactory;
 import org.apache.hadoop.hbase.CellBuilderType;
 import org.apache.hadoop.hbase.CellUtil;
@@ -51,7 +50,7 @@ public void testAppendCopyConstructor() throws IOException {
     byte[] family = Bytes.toBytes("CF-01");
 
     origin.add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(origin.getRow())
-      .setFamily(family).setQualifier(Bytes.toBytes("q")).setType(Type.Put)
+      .setFamily(family).setQualifier(Bytes.toBytes("q")).setType(Cell.Type.Put)
       .setValue(Bytes.toBytes(100)).build());
     origin.addColumn(family, Bytes.toBytes("q0"), Bytes.toBytes("value"));
     origin.setTimeRange(100, 1000);
@@ -89,7 +88,7 @@ public void testDeleteCopyConstructor() throws IOException {
     byte[] family = Bytes.toBytes("CF-01");
 
     origin.add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(origin.getRow())
-      .setFamily(family).setQualifier(Bytes.toBytes("q")).setType(Type.Delete).build());
+      .setFamily(family).setQualifier(Bytes.toBytes("q")).setType(Cell.Type.Delete).build());
     origin.addColumn(family, Bytes.toBytes("q0"));
     origin.addColumns(family, Bytes.toBytes("q1"));
     origin.addFamily(family);
@@ -187,10 +186,11 @@ public void testAddImmutableToPut() throws IOException {
     Put put = new Put(row, true);
     put
       .add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(row).setFamily(family)
-        .setQualifier(qualifier0).setTimestamp(put.getTimestamp()).setType(Type.Put)
+        .setQualifier(qualifier0).setTimestamp(put.getTimestamp()).setType(Cell.Type.Put)
         .setValue(value0).build())
       .add(CellBuilderFactory.create(CellBuilderType.SHALLOW_COPY).setRow(row).setFamily(family)
-        .setQualifier(qualifier1).setTimestamp(ts1).setType(Type.Put).setValue(value1).build());
+        .setQualifier(qualifier1).setTimestamp(ts1).setType(Cell.Type.Put).setValue(value1)
+        .build());
 
     // Verify the cell of family:qualifier0
     Cell cell0 = put.get(family, qualifier0).get(0);
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestRegionInfoDisplay.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestRegionInfoDisplay.java
index 0403ca647355..6e665dd55fc2 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestRegionInfoDisplay.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestRegionInfoDisplay.java
@@ -87,8 +87,8 @@ private void checkDescriptiveNameEquality(String descriptiveNameForDisplay, Stri
     String firstPartOrig = origDesc.substring(0, origDesc.indexOf(Bytes.toStringBinary(startKey)));
     String secondPartOrig = origDesc.substring(
       origDesc.indexOf(Bytes.toStringBinary(startKey)) + Bytes.toStringBinary(startKey).length());
-    assert (firstPart.equals(firstPartOrig));
-    assert (secondPart.equals(secondPartOrig));
+    Assert.assertTrue(firstPart.equals(firstPartOrig));
+    Assert.assertTrue(secondPart.equals(secondPartOrig));
   }
 
   private void checkEquality(RegionInfo ri, Configuration conf) throws IOException {
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestScan.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestScan.java
index 4023d745c065..4b124c68f862 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestScan.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestScan.java
@@ -164,22 +164,17 @@ public void testNullQualifier() {
   @Test
   public void testSetAuthorizations() {
     Scan scan = new Scan();
-    try {
-      scan.setAuthorizations(new Authorizations("\u002b|\u0029"));
-      scan.setAuthorizations(new Authorizations("A", "B", "0123", "A0", "1A1", "_a"));
-      scan.setAuthorizations(new Authorizations("A|B"));
-      scan.setAuthorizations(new Authorizations("A&B"));
-      scan.setAuthorizations(new Authorizations("!B"));
-      scan.setAuthorizations(new Authorizations("A", "(A)"));
-      scan.setAuthorizations(new Authorizations("A", "{A"));
-      scan.setAuthorizations(new Authorizations(" "));
-      scan.setAuthorizations(new Authorizations(":B"));
-      scan.setAuthorizations(new Authorizations("-B"));
-      scan.setAuthorizations(new Authorizations(".B"));
-      scan.setAuthorizations(new Authorizations("/B"));
-    } catch (IllegalArgumentException e) {
-      fail("should not throw exception");
-    }
+    scan.setAuthorizations(new Authorizations("A", "B", "0123", "A0", "1A1", "_a"));
+    scan.setAuthorizations(new Authorizations("A|B"));
+    scan.setAuthorizations(new Authorizations("A&B"));
+    scan.setAuthorizations(new Authorizations("!B"));
+    scan.setAuthorizations(new Authorizations("A", "(A)"));
+    scan.setAuthorizations(new Authorizations("A", "{A"));
+    scan.setAuthorizations(new Authorizations(" "));
+    scan.setAuthorizations(new Authorizations(":B"));
+    scan.setAuthorizations(new Authorizations("-B"));
+    scan.setAuthorizations(new Authorizations(".B"));
+    scan.setAuthorizations(new Authorizations("/B"));
   }
 
   @Test
@@ -192,8 +187,7 @@ public void testSetStartRowAndSetStopRow() {
       scan.withStartRow(new byte[HConstants.MAX_ROW_LENGTH + 1]);
       fail("should've thrown exception");
     } catch (IllegalArgumentException iae) {
-    } catch (Exception e) {
-      fail("expected IllegalArgumentException to be thrown");
+      // Expected
     }
 
     scan.withStopRow(null);
@@ -203,8 +197,7 @@ public void testSetStartRowAndSetStopRow() {
       scan.withStopRow(new byte[HConstants.MAX_ROW_LENGTH + 1]);
       fail("should've thrown exception");
     } catch (IllegalArgumentException iae) {
-    } catch (Exception e) {
-      fail("expected IllegalArgumentException to be thrown");
+      // Expected
     }
   }
 
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
index a7fcac95ee95..30fdbc367ff8 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
@@ -102,6 +102,7 @@ private void testIllegalArgument(String key, long value) {
       new SimpleRequestController(conf);
       fail("The " + key + " must be bigger than zero");
     } catch (IllegalArgumentException e) {
+      // Expected
     }
   }
 
@@ -115,6 +116,7 @@ public long heapSize() {
   }
 
   @Test
+  @SuppressWarnings("ArrayAsKeyOfSetOrMap")
   public void testTaskCheckerHost() throws IOException {
     final int maxTotalConcurrentTasks = 100;
     final int maxConcurrentTasksPerServer = 2;
@@ -277,6 +279,7 @@ public void testSubmittedSizeChecker() {
   }
 
   @Test
+  @SuppressWarnings("ArrayAsKeyOfSetOrMap")
   public void testTaskCountChecker() throws InterruptedIOException {
     long heapSizeOfRow = 12345;
     int maxTotalConcurrentTasks = 100;
@@ -358,10 +361,8 @@ public void testWaitForMaximumCurrentTasks() throws Exception {
       try {
         barrier.await();
         controller.waitForMaximumCurrentTasks(max.get(), 123, 1, null);
-      } catch (InterruptedIOException e) {
+      } catch (InterruptedIOException | InterruptedException | BrokenBarrierException e) {
         Assert.fail(e.getMessage());
-      } catch (InterruptedException | BrokenBarrierException e) {
-        e.printStackTrace();
       }
     };
     // First test that our runnable thread only exits when tasks is zero.
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/filter/TestKeyOnlyFilter.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/filter/TestKeyOnlyFilter.java
index 860544ba1350..0a888e838c1c 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/filter/TestKeyOnlyFilter.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/filter/TestKeyOnlyFilter.java
@@ -27,7 +27,6 @@
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HBaseCommonTestingUtil;
 import org.apache.hadoop.hbase.KeyValue;
-import org.apache.hadoop.hbase.KeyValue.Type;
 import org.apache.hadoop.hbase.KeyValueUtil;
 import org.apache.hadoop.hbase.filter.KeyOnlyFilter.KeyOnlyByteBufferExtendedCell;
 import org.apache.hadoop.hbase.filter.KeyOnlyFilter.KeyOnlyCell;
@@ -64,7 +63,8 @@ public void testKeyOnly() throws Exception {
     byte[] q = Bytes.toBytes("qual1");
     byte[] v = Bytes.toBytes("val1");
     byte[] tags = Bytes.toBytes("tag1");
-    KeyValue kv = new KeyValue(r, f, q, 0, q.length, 1234L, Type.Put, v, 0, v.length, tags);
+    KeyValue kv =
+      new KeyValue(r, f, q, 0, q.length, 1234L, KeyValue.Type.Put, v, 0, v.length, tags);
 
     ByteBuffer buffer = ByteBuffer.wrap(kv.getBuffer());
     ByteBufferKeyValue bbCell = new ByteBufferKeyValue(buffer, 0, buffer.remaining());
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestCellBlockBuilder.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestCellBlockBuilder.java
index f9c93811b4eb..fccea923635a 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestCellBlockBuilder.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestCellBlockBuilder.java
@@ -154,7 +154,7 @@ private static void timerTests(final CellBlockBuilder builder, final int count,
     StopWatch timer = new StopWatch();
     timer.start();
     for (int i = 0; i < cycles; i++) {
-      timerTest(builder, timer, count, size, codec, compressor, false);
+      timerTest(builder, count, size, codec, compressor, false);
     }
     timer.stop();
     LOG.info("Codec=" + codec + ", compression=" + compressor + ", sized=" + false + ", count="
@@ -162,16 +162,15 @@ private static void timerTests(final CellBlockBuilder builder, final int count,
     timer.reset();
     timer.start();
     for (int i = 0; i < cycles; i++) {
-      timerTest(builder, timer, count, size, codec, compressor, true);
+      timerTest(builder, count, size, codec, compressor, true);
     }
     timer.stop();
     LOG.info("Codec=" + codec + ", compression=" + compressor + ", sized=" + true + ", count="
       + count + ", size=" + size + ", + took=" + timer.getTime() + "ms");
   }
 
-  private static void timerTest(final CellBlockBuilder builder, final StopWatch timer,
-    final int count, final int size, final Codec codec, final CompressionCodec compressor,
-    final boolean sized) throws IOException {
+  private static void timerTest(final CellBlockBuilder builder, final int count, final int size,
+    final Codec codec, final CompressionCodec compressor, final boolean sized) throws IOException {
     doBuildCellBlockUndoCellBlock(builder, codec, compressor, count, size, sized);
   }
 
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestNettyRpcConnection.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestNettyRpcConnection.java
index a9c40fd3bb79..73f3653a9026 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestNettyRpcConnection.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/ipc/TestNettyRpcConnection.java
@@ -20,6 +20,7 @@
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
@@ -69,9 +70,8 @@ public static void tearDown() throws IOException {
 
   @Test
   public void testPrivateMethodExecutedInEventLoop() throws IllegalAccessException {
-    // make sure the test is executed with "-ea"
     assertThrows(AssertionError.class, () -> {
-      assert false;
+      assertTrue(false);
     });
     for (Method method : NettyRpcConnection.class.getDeclaredMethods()) {
       if (Modifier.isPrivate(method.getModifiers()) && !method.getName().contains("$")) {
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/quotas/TestQuotaGlobalsSettingsBypass.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/quotas/TestQuotaGlobalsSettingsBypass.java
index e2843180938e..a3c96eb45aa9 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/quotas/TestQuotaGlobalsSettingsBypass.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/quotas/TestQuotaGlobalsSettingsBypass.java
@@ -143,6 +143,7 @@ void expectFailure(QuotaSettings one, QuotaSettings two) throws IOException {
       one.merge(two);
       fail("Expected to see an Exception merging " + two + " into " + one);
     } catch (IllegalArgumentException e) {
+      // Expected
     }
   }
 }
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/security/TestHBaseSaslRpcClient.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/security/TestHBaseSaslRpcClient.java
index 60bd80fb58f7..7b42ba224fac 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/security/TestHBaseSaslRpcClient.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/security/TestHBaseSaslRpcClient.java
@@ -138,14 +138,8 @@ public void testDigestSaslClientCallbackHandlerWithException() {
   @Test
   public void testHBaseSaslRpcClientCreation() throws Exception {
     // creation kerberos principal check section
-    assertFalse(assertSuccessCreationKerberosPrincipal(null));
-    assertFalse(assertSuccessCreationKerberosPrincipal("DOMAIN.COM"));
-    assertFalse(assertSuccessCreationKerberosPrincipal("principal/DOMAIN.COM"));
-    if (!assertSuccessCreationKerberosPrincipal("principal/localhost@DOMAIN.COM")) {
-      // XXX: This can fail if kerberos support in the OS is not sane, see HBASE-10107.
-      // For now, don't assert, just warn
-      LOG.warn("Could not create a SASL client with valid Kerberos credential");
-    }
+    // Note this is mocked in a way that doesn't care about principal names
+    assertFalse(assertSuccessCreationKerberos());
 
     // creation digest principal check section
     assertFalse(assertSuccessCreationDigestPrincipal(null, null));
@@ -155,9 +149,8 @@ public void testHBaseSaslRpcClientCreation() throws Exception {
     assertTrue(assertSuccessCreationDigestPrincipal(DEFAULT_USER_NAME, DEFAULT_USER_PASSWORD));
 
     // creation simple principal check section
-    assertFalse(assertSuccessCreationSimplePrincipal("", ""));
-    assertFalse(assertSuccessCreationSimplePrincipal(null, null));
-    assertFalse(assertSuccessCreationSimplePrincipal(DEFAULT_USER_NAME, DEFAULT_USER_PASSWORD));
+    // Note this is mocked in a way that doesn't care about principal names
+    assertFalse(assertSuccessCreationSimple());
 
     // exceptions check section
     assertTrue(assertIOExceptionThenSaslClientIsNull(DEFAULT_USER_NAME, DEFAULT_USER_PASSWORD));
@@ -245,10 +238,11 @@ public SaslClient createClient(Configuration conf, InetAddress serverAddress,
     }
   }
 
-  private boolean assertSuccessCreationKerberosPrincipal(String principal) {
+  private boolean assertSuccessCreationKerberos() {
     HBaseSaslRpcClient rpcClient = null;
     try {
-      rpcClient = createSaslRpcClientForKerberos(principal);
+      // createSaslRpcClientForKerberos is mocked in a way that doesn't care about principal names
+      rpcClient = createSaslRpcClientForKerberos();
     } catch (Exception ex) {
       LOG.error(ex.getMessage(), ex);
     }
@@ -268,17 +262,17 @@ private boolean assertSuccessCreationDigestPrincipal(String principal, String pa
     return rpcClient != null;
   }
 
-  private boolean assertSuccessCreationSimplePrincipal(String principal, String password) {
+  private boolean assertSuccessCreationSimple() {
     HBaseSaslRpcClient rpcClient = null;
     try {
-      rpcClient = createSaslRpcClientSimple(principal, password);
+      rpcClient = createSaslRpcClientSimple();
     } catch (Exception ex) {
       LOG.error(ex.getMessage(), ex);
     }
     return rpcClient != null;
   }
 
-  private HBaseSaslRpcClient createSaslRpcClientForKerberos(String principal) throws IOException {
+  private HBaseSaslRpcClient createSaslRpcClientForKerberos() throws IOException {
     return new HBaseSaslRpcClient(HBaseConfiguration.create(),
       new GssSaslClientAuthenticationProvider(), createTokenMock(), Mockito.mock(InetAddress.class),
       Mockito.mock(SecurityInfo.class), false);
@@ -294,8 +288,7 @@ private Token<? extends TokenIdentifier> createTokenMockWithCredentials(String p
     return token;
   }
 
-  private HBaseSaslRpcClient createSaslRpcClientSimple(String principal, String password)
-    throws IOException {
+  private HBaseSaslRpcClient createSaslRpcClientSimple() throws IOException {
     return new HBaseSaslRpcClient(HBaseConfiguration.create(),
       new SimpleSaslClientAuthenticationProvider(), createTokenMock(),
       Mockito.mock(InetAddress.class), Mockito.mock(SecurityInfo.class), false);
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestRoundRobinPoolMap.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestRoundRobinPoolMap.java
index d7ce6265b8c5..04ba2570eac8 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestRoundRobinPoolMap.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestRoundRobinPoolMap.java
@@ -120,10 +120,10 @@ public void testMultiThreadedRoundRobin() throws ExecutionException, Interrupted
           String value = Integer.toString(id.getAndIncrement());
           String result = poolMap.getOrCreate(key, () -> value);
           results.add(result);
-
-          Thread.yield();
+          // Sleep for a short time to ensure a yield. Thread#yield has platform dependent behavior.
+          Thread.sleep(10);
         }
-      } catch (IOException e) {
+      } catch (Exception e) {
         throw new CompletionException(e);
       }
     };
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestThreadLocalPoolMap.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestThreadLocalPoolMap.java
index 45f533f1a730..d83944ef7f3a 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestThreadLocalPoolMap.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/util/TestThreadLocalPoolMap.java
@@ -95,10 +95,10 @@ public void testLocality() throws ExecutionException, InterruptedException {
         for (int i = 0; i < 3; i++) {
           String result = poolMap.getOrCreate(key, () -> myId);
           assertEquals(myId, result);
-
-          Thread.yield();
+          // Sleep for a short period of time to yield. Thread#yield is platform dependent.
+          Thread.sleep(10);
         }
-      } catch (IOException e) {
+      } catch (Exception e) {
         throw new CompletionException(e);
       }
     };

From 21ee02f2932e68633e170a449e2764551a958f8f Mon Sep 17 00:00:00 2001
From: Andrew Purtell <apurtell@apache.org>
Date: Mon, 25 Jul 2022 16:28:00 -0700
Subject: [PATCH 2/3] Address review feedback and additional cleanups

---
 .../org/apache/hadoop/hbase/client/Admin.java    | 16 +++++++---------
 .../org/apache/hadoop/hbase/client/Append.java   |  2 +-
 .../hbase/coprocessor/ColumnInterpreter.java     |  6 ++++++
 .../hbase/filter/BigDecimalComparator.java       |  1 +
 .../hadoop/hbase/filter/BinaryComparator.java    |  1 +
 .../hbase/filter/BinaryComponentComparator.java  |  1 +
 .../hbase/filter/BinaryPrefixComparator.java     |  1 +
 .../hadoop/hbase/filter/BitComparator.java       |  1 +
 .../hbase/filter/ColumnCountGetFilter.java       |  1 +
 .../hbase/filter/ColumnPaginationFilter.java     |  1 +
 .../hadoop/hbase/filter/ColumnPrefixFilter.java  |  2 +-
 .../hadoop/hbase/filter/ColumnRangeFilter.java   |  1 +
 .../hadoop/hbase/filter/ColumnValueFilter.java   |  2 ++
 .../hbase/filter/DependentColumnFilter.java      |  1 +
 .../apache/hadoop/hbase/filter/FamilyFilter.java |  4 +++-
 .../org/apache/hadoop/hbase/filter/Filter.java   |  4 +++-
 .../apache/hadoop/hbase/filter/FilterList.java   |  1 +
 .../hadoop/hbase/filter/FirstKeyOnlyFilter.java  |  2 +-
 .../FirstKeyValueMatchingQualifiersFilter.java   |  1 +
 .../hadoop/hbase/filter/FuzzyRowFilter.java      |  1 +
 .../hadoop/hbase/filter/InclusiveStopFilter.java |  1 +
 .../hadoop/hbase/filter/KeyOnlyFilter.java       |  1 +
 .../hadoop/hbase/filter/LongComparator.java      |  2 +-
 .../hadoop/hbase/filter/MultiRowRangeFilter.java |  5 +++--
 .../hbase/filter/MultipleColumnPrefixFilter.java |  1 +
 .../hadoop/hbase/filter/NullComparator.java      |  1 +
 .../apache/hadoop/hbase/filter/PageFilter.java   |  1 +
 .../apache/hadoop/hbase/filter/ParseFilter.java  |  1 -
 .../apache/hadoop/hbase/filter/PrefixFilter.java |  2 +-
 .../hadoop/hbase/filter/QualifierFilter.java     |  2 +-
 .../hadoop/hbase/filter/RandomRowFilter.java     |  1 +
 .../hbase/filter/RegexStringComparator.java      |  1 +
 .../apache/hadoop/hbase/filter/RowFilter.java    |  4 +++-
 .../filter/SingleColumnValueExcludeFilter.java   |  1 +
 .../hbase/filter/SingleColumnValueFilter.java    |  1 +
 .../apache/hadoop/hbase/filter/SkipFilter.java   |  4 +++-
 .../hadoop/hbase/filter/SubstringComparator.java |  5 +++--
 .../hadoop/hbase/filter/TimestampsFilter.java    |  1 +
 .../apache/hadoop/hbase/filter/ValueFilter.java  |  4 +++-
 .../hadoop/hbase/filter/WhileMatchFilter.java    |  2 +-
 .../apache/hadoop/hbase/security/SaslUtil.java   |  6 ++++--
 ...AbstractSaslClientAuthenticationProvider.java |  1 -
 .../client/TestSimpleRequestController.java      |  7 +++----
 43 files changed, 72 insertions(+), 33 deletions(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
index 34f7cf43308a..bdb96ef3c14a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
@@ -188,8 +188,8 @@ default TableName[] listTableNames(Pattern pattern) throws IOException {
    * Get a table descriptor.
    * @param tableName as a {@link TableName}
    * @return the tableDescriptor
-   * @throws org.apache.hadoop.hbase.TableNotFoundException if the table was not found
-   * @throws IOException                                    if a remote or network exception occurs
+   * @throws TableNotFoundException if the table was not found
+   * @throws IOException            if a remote or network exception occurs
    */
   TableDescriptor getDescriptor(TableName tableName) throws TableNotFoundException, IOException;
 
@@ -198,7 +198,7 @@ default TableName[] listTableNames(Pattern pattern) throws IOException {
    * @param desc table descriptor for table
    * @throws IllegalArgumentException                          if the table name is reserved
    * @throws org.apache.hadoop.hbase.MasterNotRunningException if master is not running
-   * @throws org.apache.hadoop.hbase.TableExistsException      if table already exists (If
+   * @throws TableExistsException                              if table already exists (If
    *                                                           concurrent threads, the table may
    *                                                           have been created between
    *                                                           test-for-existence and
@@ -224,7 +224,7 @@ default void createTable(TableDescriptor desc) throws IOException {
    *                                                           occurs
    * @throws IllegalArgumentException                          if the table name is reserved
    * @throws org.apache.hadoop.hbase.MasterNotRunningException if master is not running
-   * @throws org.apache.hadoop.hbase.TableExistsException      if table already exists (If
+   * @throws TableExistsException                              if table already exists (If
    *                                                           concurrent threads, the table may
    *                                                           have been created between
    *                                                           test-for-existence and
@@ -243,7 +243,7 @@ void createTable(TableDescriptor desc, byte[] startKey, byte[] endKey, int numRe
    *                                                           split keys are repeated and if the
    *                                                           split key has empty byte array.
    * @throws org.apache.hadoop.hbase.MasterNotRunningException if master is not running
-   * @throws org.apache.hadoop.hbase.TableExistsException      if table already exists (If
+   * @throws TableExistsException                              if table already exists (If
    *                                                           concurrent threads, the table may
    *                                                           have been created between
    *                                                           test-for-existence and
@@ -1343,10 +1343,8 @@ Future<Boolean> abortProcedureAsync(long procId, boolean mayInterruptIfRunning)
    * this method returns. As a side effect of this call, the named region server may schedule store
    * flushes at the request of the wal.
    * @param serverName The servername of the regionserver.
-   * @throws IOException                                                      if a remote or network
-   *                                                                          exception occurs
-   * @throws org.apache.hadoop.hbase.regionserver.wal.FailedLogCloseException if we failed to close
-   *                                                                          the WAL
+   * @throws IOException             if a remote or network exception occurs
+   * @throws FailedLogCloseException if we failed to close the WAL
    */
   void rollWALWriter(ServerName serverName) throws IOException, FailedLogCloseException;
 
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
index 9c1dbd0922c6..6304065ae37b 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Append.java
@@ -49,7 +49,7 @@
 @InterfaceAudience.Public
 public class Append extends Mutation {
   private static final Logger LOG = LoggerFactory.getLogger(Append.class);
-  private static final long HEAP_OVERHEAD = (long) (ClassSize.REFERENCE + ClassSize.TIMERANGE);
+  private static final long HEAP_OVERHEAD = (long) ClassSize.REFERENCE + ClassSize.TIMERANGE;
   private TimeRange tr = TimeRange.allTime();
 
   /**
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
index af9f5d9ff444..73e3b53eb369 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/coprocessor/ColumnInterpreter.java
@@ -40,6 +40,12 @@
  * {@link ColumnInterpreter#castToReturnType(Object)} which takes a &lt;T&gt; type and returns a
  * &lt;S&gt; type. The AggregateIm&gt;lementation uses PB messages to initialize the user's
  * ColumnInterpreter implementation, and for sending the responses back to AggregationClient.
+ * <p>
+ * &lt;T&gt; Cell value data type<br>
+ * &lt;S&gt; Promoted data type<br>
+ * &lt;P&gt; PB message that is used to transport initializer specific bytes<br>
+ * &lt;Q&gt; PB message that is used to transport Cell (&lt;T&gt;) instance<br>
+ * &lt;R&gt; PB message that is used to transport Promoted (&lt;S&gt;) instance
  */
 @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
 @InterfaceStability.Evolving
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
index f3ec888f9c9e..b37bec4fc51a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BigDecimalComparator.java
@@ -85,6 +85,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link BigDecimalComparator}
    * @param pbBytes A pb serialized {@link BigDecimalComparator} instance
    * @return An instance of {@link BigDecimalComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static BigDecimalComparator parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
index 749d055f8ebd..079cee8e6424 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComparator.java
@@ -67,6 +67,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link BinaryComparator}
    * @param pbBytes A pb serialized {@link BinaryComparator} instance
    * @return An instance of {@link BinaryComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static BinaryComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
index 1e2250fda45c..6e0ff7edf527 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryComponentComparator.java
@@ -89,6 +89,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link BinaryComponentComparator}
    * @param pbBytes A pb serialized {@link BinaryComponentComparator} instance
    * @return An instance of {@link BinaryComponentComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static BinaryComponentComparator parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
index 00e5fdd7a4e7..b9cbcc0826bd 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java
@@ -71,6 +71,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link BinaryPrefixComparator}
    * @param pbBytes A pb serialized {@link BinaryPrefixComparator} instance
    * @return An instance of {@link BinaryPrefixComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static BinaryPrefixComparator parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
index f421214411b8..d19738d53575 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/BitComparator.java
@@ -77,6 +77,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link BitComparator}
    * @param pbBytes A pb serialized {@link BitComparator} instance
    * @return An instance of {@link BitComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static BitComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
index d15b5c5bbae7..af11ac5f81a5 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnCountGetFilter.java
@@ -91,6 +91,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link ColumnCountGetFilter}
    * @param pbBytes A pb serialized {@link ColumnCountGetFilter} instance
    * @return An instance of {@link ColumnCountGetFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static ColumnCountGetFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
index cf29cf02a38d..88f18100bbd9 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPaginationFilter.java
@@ -161,6 +161,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link ColumnPaginationFilter}
    * @param pbBytes A pb serialized {@link ColumnPaginationFilter} instance
    * @return An instance of {@link ColumnPaginationFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static ColumnPaginationFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
index 209b5d72f6ea..3b8df1d15c68 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnPrefixFilter.java
@@ -114,7 +114,7 @@ public byte[] toByteArray() {
    * Parses a serialized representation of the {@link ColumnPrefixFilter}
    * @param pbBytes A pb serialized {@link ColumnPrefixFilter} instance
    * @return An instance of {@link ColumnPrefixFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static ColumnPrefixFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
index 300e3dcd2552..c9a7902d1e46 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnRangeFilter.java
@@ -160,6 +160,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link ColumnRangeFilter}
    * @param pbBytes A pb serialized {@link ColumnRangeFilter} instance
    * @return An instance of {@link ColumnRangeFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static ColumnRangeFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
index 2ee5ac31748a..e7c06d44aeff 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ColumnValueFilter.java
@@ -171,6 +171,8 @@ FilterProtos.ColumnValueFilter convert() {
    * Parse a serialized representation of {@link ColumnValueFilter}
    * @param pbBytes A pb serialized {@link ColumnValueFilter} instance
    * @return An instance of {@link ColumnValueFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static ColumnValueFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.ColumnValueFilter proto;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
index 5c5fa3813645..3d052fc68aae 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/DependentColumnFilter.java
@@ -202,6 +202,7 @@ public byte[] toByteArray() {
    * Parse a seralized representation of {@link DependentColumnFilter}
    * @param pbBytes A pb serialized {@link DependentColumnFilter} instance
    * @return An instance of {@link DependentColumnFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static DependentColumnFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
index 5991752ac898..73f859f76aea 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FamilyFilter.java
@@ -84,7 +84,9 @@ public byte[] toByteArray() {
   /**
    * Parse the serialized representation of {@link FamilyFilter}
    * @param pbBytes A pb serialized {@link FamilyFilter} instance
-   * @return An instance of {@link FamilyFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link FamilyFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static FamilyFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.FamilyFilter proto;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
index 2d6882559e59..a5f5efcaba17 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/Filter.java
@@ -205,7 +205,9 @@ public enum ReturnCode {
    * Concrete implementers can signal a failure condition in their code by throwing an
    * {@link IOException}.
    * @param pbBytes A pb serialized {@link Filter} instance
-   * @return An instance of {@link Filter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link Filter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static Filter parseFrom(final byte[] pbBytes) throws DeserializationException {
     throw new DeserializationException(
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
index d9a817088d7c..3b7c136c6e1f 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java
@@ -197,6 +197,7 @@ public byte[] toByteArray() throws IOException {
    * Parse a seralized representation of {@link FilterList}
    * @param pbBytes A pb serialized {@link FilterList} instance
    * @return An instance of {@link FilterList} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static FilterList parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
index e2fa95c33452..6f5e04bbd8d8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyOnlyFilter.java
@@ -88,7 +88,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link FirstKeyOnlyFilter}
    * @param pbBytes A pb serialized {@link FirstKeyOnlyFilter} instance
    * @return An instance of {@link FirstKeyOnlyFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static FirstKeyOnlyFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
index 162b61c8934c..67354b304f5a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FirstKeyValueMatchingQualifiersFilter.java
@@ -36,6 +36,7 @@ public class FirstKeyValueMatchingQualifiersFilter extends FirstKeyOnlyFilter {
    * @param pbBytes A pb serialized {@link FirstKeyValueMatchingQualifiersFilter} instance
    * @return An instance of {@link FirstKeyValueMatchingQualifiersFilter} made from
    *         <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static FirstKeyValueMatchingQualifiersFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
index 5726413d7649..1506eca5df66 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FuzzyRowFilter.java
@@ -268,6 +268,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link FuzzyRowFilter}
    * @param pbBytes A pb serialized {@link FuzzyRowFilter} instance
    * @return An instance of {@link FuzzyRowFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static FuzzyRowFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
index c365e94cfbd2..a9d4e7806880 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/InclusiveStopFilter.java
@@ -89,6 +89,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link InclusiveStopFilter}
    * @param pbBytes A pb serialized {@link InclusiveStopFilter} instance
    * @return An instance of {@link InclusiveStopFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static InclusiveStopFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
index 47a586a5a2af..e2711a774aa5 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/KeyOnlyFilter.java
@@ -105,6 +105,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link KeyOnlyFilter}
    * @param pbBytes A pb serialized {@link KeyOnlyFilter} instance
    * @return An instance of {@link KeyOnlyFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static KeyOnlyFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
index bc7d23ae1d02..c71afa098fe9 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/LongComparator.java
@@ -65,7 +65,7 @@ public byte[] toByteArray() {
    * Parses a serialized representation of {@link LongComparator}
    * @param pbBytes A pb serialized {@link LongComparator} instance
    * @return An instance of {@link LongComparator} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static LongComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
index 3526bbcb0684..85fae7b0a992 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultiRowRangeFilter.java
@@ -200,7 +200,8 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link MultiRowRangeFilter}
    * @param pbBytes A pb serialized instance
    * @return An instance of {@link MultiRowRangeFilter}
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static MultiRowRangeFilter parseFrom(final byte[] pbBytes)
     throws DeserializationException {
@@ -722,7 +723,7 @@ public void setFoundFirstRange() {
     /**
      * Gets the RowRange at the given offset.
      */
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({ "unchecked", "TypeParameterUnusedInFormals" })
     public <T extends BasicRowRange> T get(int i) {
       return (T) ranges.get(i);
     }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
index 456290aaae0e..168257cd2f71 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/MultipleColumnPrefixFilter.java
@@ -131,6 +131,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link MultipleColumnPrefixFilter}
    * @param pbBytes A pb serialized {@link MultipleColumnPrefixFilter} instance
    * @return An instance of {@link MultipleColumnPrefixFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static MultipleColumnPrefixFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
index b7597771458a..ea8a5abd3545 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/NullComparator.java
@@ -74,6 +74,7 @@ public byte[] toByteArray() {
    * Parse the serialized representation of {@link NullComparator}
    * @param pbBytes A pb serialized {@link NullComparator} instance
    * @return An instance of {@link NullComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static NullComparator parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
index 5039dde14ec8..45c91921db8a 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PageFilter.java
@@ -103,6 +103,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link PageFilter}
    * @param pbBytes A pb serialized {@link PageFilter} instance
    * @return An instance of {@link PageFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static PageFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
index 9951330f4535..c9bd7a1a55c8 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ParseFilter.java
@@ -109,7 +109,6 @@ public Filter parseFilterString(String filterString) throws CharacterCodingExcep
    * @param filterStringAsByteArray filter string given by the user
    * @return filter object we constructed
    */
-  @SuppressWarnings("JdkObsolete")
   public Filter parseFilterString(byte[] filterStringAsByteArray) throws CharacterCodingException {
     // stack for the operators and parenthesis
     Stack<ByteBuffer> operatorStack = new Stack<>();
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
index e50e462187e8..c6d76a2f0d11 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/PrefixFilter.java
@@ -113,7 +113,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link PrefixFilter}
    * @param pbBytes A pb serialized {@link PrefixFilter} instance
    * @return An instance of {@link PrefixFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static PrefixFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
index baf13eda2fae..e11e2ad4857e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/QualifierFilter.java
@@ -79,7 +79,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link QualifierFilter}
    * @param pbBytes A pb serialized {@link QualifierFilter} instance
    * @return An instance of {@link QualifierFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static QualifierFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
index d68a4d07bd89..099f38026feb 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RandomRowFilter.java
@@ -110,6 +110,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link RandomRowFilter}
    * @param pbBytes A pb serialized {@link RandomRowFilter} instance
    * @return An instance of {@link RandomRowFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static RandomRowFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
index 9c9ccf5d049d..9efa563b4324 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RegexStringComparator.java
@@ -155,6 +155,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link RegexStringComparator}
    * @param pbBytes A pb serialized {@link RegexStringComparator} instance
    * @return An instance of {@link RegexStringComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static RegexStringComparator parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
index 51a1c49ff143..017185670be2 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/RowFilter.java
@@ -98,7 +98,9 @@ public byte[] toByteArray() {
   /**
    * Parse a serialized representation of {@link RowFilter}
    * @param pbBytes A pb serialized {@link RowFilter} instance
-   * @return An instance of {@link RowFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link RowFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static RowFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.RowFilter proto;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
index 2aedca5bfbdb..14bdc04a754c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueExcludeFilter.java
@@ -125,6 +125,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link SingleColumnValueExcludeFilter}
    * @param pbBytes A pb serialized {@link SingleColumnValueExcludeFilter} instance
    * @return An instance of {@link SingleColumnValueExcludeFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static SingleColumnValueExcludeFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
index 964a04429c52..7be5ce914058 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SingleColumnValueFilter.java
@@ -287,6 +287,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link SingleColumnValueFilter}
    * @param pbBytes A pb serialized {@link SingleColumnValueFilter} instance
    * @return An instance of {@link SingleColumnValueFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static SingleColumnValueFilter parseFrom(final byte[] pbBytes)
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
index 9d2bf1adefc7..a5149592f614 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SkipFilter.java
@@ -107,7 +107,9 @@ public byte[] toByteArray() throws IOException {
   /**
    * Parse a serialized representation of {@link SkipFilter}
    * @param pbBytes A pb serialized {@link SkipFilter} instance
-   * @return An instance of {@link SkipFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link SkipFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static SkipFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.SkipFilter proto;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
index 995b37c3f2ff..8312d3f673f0 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/SubstringComparator.java
@@ -78,8 +78,9 @@ public byte[] toByteArray() {
   /**
    * Parse a serialized representation of {@link SubstringComparator}
    * @param pbBytes A pb serialized {@link SubstringComparator} instance
-   * @return An instance of {@link SubstringComparator} made from <code>bytes</code> n * @see
-   *         #toByteArray
+   * @return An instance of {@link SubstringComparator} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static SubstringComparator parseFrom(final byte[] pbBytes)
     throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
index 62512fc128af..b3f821d75e49 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/TimestampsFilter.java
@@ -170,6 +170,7 @@ public byte[] toByteArray() {
    * Parse a serialized representation of {@link TimestampsFilter}
    * @param pbBytes A pb serialized {@link TimestampsFilter} instance
    * @return An instance of {@link TimestampsFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static TimestampsFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
index a2d00930992b..0056a3aff0da 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/ValueFilter.java
@@ -80,7 +80,9 @@ public byte[] toByteArray() {
   /**
    * Parse a serialized representation of {@link ValueFilter}
    * @param pbBytes A pb serialized {@link ValueFilter} instance
-   * @return An instance of {@link ValueFilter} made from <code>bytes</code> n * @see #toByteArray
+   * @return An instance of {@link ValueFilter} made from <code>bytes</code>
+   * @throws DeserializationException if an error occurred
+   * @see #toByteArray
    */
   public static ValueFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
     FilterProtos.ValueFilter proto;
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
index aae09bee1806..65cd03042b0c 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/filter/WhileMatchFilter.java
@@ -106,7 +106,7 @@ public byte[] toByteArray() throws IOException {
    * Parse a serialized representation of {@link WhileMatchFilter}
    * @param pbBytes A pb serialized {@link WhileMatchFilter} instance
    * @return An instance of {@link WhileMatchFilter} made from <code>bytes</code>
-   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException if an error occurred
+   * @throws DeserializationException if an error occurred
    * @see #toByteArray
    */
   public static WhileMatchFilter parseFrom(final byte[] pbBytes) throws DeserializationException {
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
index 122ad8db82fb..7feb482824ab 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase.security;
 
 import java.util.Base64;
+import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 import javax.security.sasl.Sasl;
@@ -64,7 +65,8 @@ public boolean matches(String stringQop) {
 
   /** Splitting fully qualified Kerberos name into parts */
   public static String[] splitKerberosName(String fullName) {
-    return fullName.split("[/@]");
+    List<String> result = Splitter.onPattern("[/@]").splitToList(fullName);
+    return result.toArray(new String[result.size()]);
   }
 
   public static String encodeIdentifier(byte[] identifier) {
@@ -105,7 +107,7 @@ public static Map<String, String> initSaslProperties(String rpcProtection) {
       saslQop = QualityOfProtection.AUTHENTICATION.getSaslQop();
     } else {
       StringBuilder saslQopBuilder = new StringBuilder();
-      for (String s : Splitter.on(',').splitToList(rpcProtection)) {
+      for (String s : Splitter.on(',').split(rpcProtection)) {
         QualityOfProtection qop = getQop(s);
         saslQopBuilder.append(",").append(qop.getSaslQop());
       }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
index eb91edb3e801..e9990066050e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/provider/AbstractSaslClientAuthenticationProvider.java
@@ -48,7 +48,6 @@ public final int hashCode() {
   }
 
   @Override
-  @SuppressWarnings("EqualsUsingHashCode")
   public final boolean equals(Object o) {
     // SaslClientAuthProviders should be unique via their hashCode().
     if (o instanceof AbstractSaslClientAuthenticationProvider) {
diff --git a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
index 30fdbc367ff8..17dcfb508d54 100644
--- a/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
+++ b/hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestSimpleRequestController.java
@@ -27,6 +27,7 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.TreeMap;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -116,14 +117,13 @@ public long heapSize() {
   }
 
   @Test
-  @SuppressWarnings("ArrayAsKeyOfSetOrMap")
   public void testTaskCheckerHost() throws IOException {
     final int maxTotalConcurrentTasks = 100;
     final int maxConcurrentTasksPerServer = 2;
     final int maxConcurrentTasksPerRegion = 1;
     final AtomicLong tasksInProgress = new AtomicLong(0);
     final Map<ServerName, AtomicInteger> taskCounterPerServer = new HashMap<>();
-    final Map<byte[], AtomicInteger> taskCounterPerRegion = new HashMap<>();
+    final Map<byte[], AtomicInteger> taskCounterPerRegion = new TreeMap<>(Bytes.BYTES_COMPARATOR);
     SimpleRequestController.TaskCountChecker countChecker =
       new SimpleRequestController.TaskCountChecker(maxTotalConcurrentTasks,
         maxConcurrentTasksPerServer, maxConcurrentTasksPerRegion, tasksInProgress,
@@ -279,7 +279,6 @@ public void testSubmittedSizeChecker() {
   }
 
   @Test
-  @SuppressWarnings("ArrayAsKeyOfSetOrMap")
   public void testTaskCountChecker() throws InterruptedIOException {
     long heapSizeOfRow = 12345;
     int maxTotalConcurrentTasks = 100;
@@ -287,7 +286,7 @@ public void testTaskCountChecker() throws InterruptedIOException {
     int maxConcurrentTasksPerRegion = 1;
     AtomicLong tasksInProgress = new AtomicLong(0);
     Map<ServerName, AtomicInteger> taskCounterPerServer = new HashMap<>();
-    Map<byte[], AtomicInteger> taskCounterPerRegion = new HashMap<>();
+    Map<byte[], AtomicInteger> taskCounterPerRegion = new TreeMap<>(Bytes.BYTES_COMPARATOR);
     SimpleRequestController.TaskCountChecker checker = new SimpleRequestController.TaskCountChecker(
       maxTotalConcurrentTasks, maxConcurrentTasksPerServer, maxConcurrentTasksPerRegion,
       tasksInProgress, taskCounterPerServer, taskCounterPerRegion);

From a26e02dd3185dff2533da31ed3fe2fde165f9c8e Mon Sep 17 00:00:00 2001
From: Andrew Purtell <apurtell@apache.org>
Date: Tue, 26 Jul 2022 14:47:26 -0700
Subject: [PATCH 3/3] More review feedback

---
 .../org/apache/hadoop/hbase/client/ClientIdGenerator.java     | 3 ++-
 .../main/java/org/apache/hadoop/hbase/security/SaslUtil.java  | 4 +---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
index 02df5dab2b91..ee497ef56c5f 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ClientIdGenerator.java
@@ -28,6 +28,7 @@
 import org.slf4j.LoggerFactory;
 
 import org.apache.hbase.thirdparty.com.google.common.base.Splitter;
+import org.apache.hbase.thirdparty.com.google.common.collect.Iterators;
 
 /**
  * The class that is able to determine some unique strings for the client, such as an IP address,
@@ -67,7 +68,7 @@ public static Long getPid() {
     List<String> nameParts = Splitter.on('@').splitToList(name);
     if (nameParts.size() == 2) { // 12345@somewhere
       try {
-        return Long.parseLong(nameParts.iterator().next()); // first element
+        return Long.parseLong(Iterators.get(nameParts.iterator(), 0));
       } catch (NumberFormatException ex) {
         LOG.warn("Failed to get PID from [" + name + "]", ex);
       }
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
index 7feb482824ab..dfb0a49db4a2 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/security/SaslUtil.java
@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.security;
 
 import java.util.Base64;
-import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 import javax.security.sasl.Sasl;
@@ -65,8 +64,7 @@ public boolean matches(String stringQop) {
 
   /** Splitting fully qualified Kerberos name into parts */
   public static String[] splitKerberosName(String fullName) {
-    List<String> result = Splitter.onPattern("[/@]").splitToList(fullName);
-    return result.toArray(new String[result.size()]);
+    return Splitter.onPattern("[/@]").splitToStream(fullName).toArray(String[]::new);
   }
 
   public static String encodeIdentifier(byte[] identifier) {