diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/local/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/local/package-info.java
index 48d6644e99b9e..7d9b829f7d319 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/local/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/local/package-info.java
@@ -15,6 +15,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Filesystem implementations that allow Hadoop to read directly from
+ * the local file system.
+ */
 @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
 @InterfaceStability.Unstable
 package org.apache.hadoop.fs.local;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/package-info.java
index 92720bff69b16..2f0542aa69690 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Support for the execution of a file system command.
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.fs.shell;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/http/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/http/package-info.java
index 32bbbf223073a..b1710e0f9cbea 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/http/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/http/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Support for embedded HTTP services.
+ */
 @InterfaceAudience.LimitedPrivate({"HBase", "HDFS", "MapReduce"})
 @InterfaceStability.Unstable
 package org.apache.hadoop.http;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/bzip2/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/bzip2/package-info.java
index 785170eaf6297..9973b78e39acd 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/bzip2/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/bzip2/package-info.java
@@ -15,6 +15,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Implementation of compression/decompression for the BZip2
+ * compression algorithm.
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.compress.bzip2;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/lz4/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/lz4/package-info.java
index 11827f1748628..438dfdea3e7be 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/lz4/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/lz4/package-info.java
@@ -15,6 +15,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Implementation of compression/decompression for the LZ4
+ * compression algorithm.
+ *
+ * @see <a href="http://code.google.com/p/lz4/">LZ4</a>
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.compress.lz4;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/snappy/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/snappy/package-info.java
index eedf6550833b1..320fd026a1d88 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/snappy/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/snappy/package-info.java
@@ -15,6 +15,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Implementation of compression/decompression for the Snappy
+ * compression algorithm.
+ *
+ * @see <a href="http://code.google.com/p/snappy/">Snappy</a>
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.compress.snappy;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/package-info.java
index 33d0a8d7cebf8..515eb3498f206 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/package-info.java
@@ -15,6 +15,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Implementation of compression/decompression based on the popular
+ * gzip compressed file format.
+ *
+ * @see <a href="http://www.gzip.org/">gzip</a>
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.compress.zlib;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zstd/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zstd/package-info.java
index 9069070f73a45..7214bf8582b62 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zstd/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zstd/package-info.java
@@ -15,6 +15,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Implementation of compression/decompression based on the zStandard
+ * compression algorithm.
+ *
+ * @see <a href="https://github.com/facebook/zstd">zStandard</a>
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.compress.zstd;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/package-info.java
index 346f895e6507f..7e47b3b54afcd 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/package-info.java
@@ -15,6 +15,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Various native IO-related calls not available in Java.  These
+ * functions should generally be used alongside a fallback to another
+ * more portable mechanism.
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.io.nativeio;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/authorize/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/authorize/package-info.java
index e1060e2196dcd..3c75a2427d8b8 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/authorize/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/authorize/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Support for service-level authorization.
+ */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 package org.apache.hadoop.security.authorize;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/http/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/http/package-info.java
index 8e9398eb67982..a58b3cdcfb980 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/http/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/http/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Filters for HTTP service security.
+ */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 package org.apache.hadoop.security.http;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/package-info.java
index c85f967ab67c4..0b3b8c4694411 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * ZooKeeper secret manager for TokenIdentifiers and DelegationKeys.
+ */
 @InterfaceAudience.LimitedPrivate({"HBase", "HDFS", "MapReduce"})
 @InterfaceStability.Evolving
 package org.apache.hadoop.security.token.delegation;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/package-info.java
index e015056b43e88..cdf4e61050ddc 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Support for delegation tokens.
+ */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 package org.apache.hadoop.security.token;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/package-info.java
index 3716485549968..81409382648b4 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/package-info.java
@@ -15,6 +15,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * Support for services.
+ */
 @InterfaceAudience.Public
 package org.apache.hadoop.service;
 import org.apache.hadoop.classification.InterfaceAudience;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/concurrent/package-info.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/concurrent/package-info.java
index 2effb65872eb6..871005adc0cec 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/concurrent/package-info.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/concurrent/package-info.java
@@ -1,5 +1,4 @@
 /*
- * *
  *  Licensed to the Apache Software Foundation (ASF) under one
  *  or more contributor license agreements.  See the NOTICE file
  *  distributed with this work for additional information
@@ -15,9 +14,11 @@
  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
- * /
  */
 
+/**
+ * Support for concurrent execution.
+ */
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 package org.apache.hadoop.util.concurrent;