HBASE-27203 Clean up error-prone findings in hbase-client

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 <qualifier,regioninfo> 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) {

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;

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()
    */

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()

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();
 

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();

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());

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;

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();
 

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();
       }

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();

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(),

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();

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