diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/rm/TestRMContainerAllocator.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/rm/TestRMContainerAllocator.java
index 8f51e35..4ee0a14 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/rm/TestRMContainerAllocator.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/rm/TestRMContainerAllocator.java
@@ -141,7 +141,6 @@
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.SchedulerEvent;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.fifo.FifoScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.security.AMRMTokenSecretManager;
-import org.apache.hadoop.yarn.server.timelineservice.security.TimelineV2DelegationTokenSecretManagerService.TimelineV2DelegationTokenSecretManager;
 import org.apache.hadoop.yarn.server.utils.BuilderUtils;
 import org.apache.hadoop.yarn.util.Clock;
 import org.apache.hadoop.yarn.util.ControlledClock;
@@ -776,7 +775,7 @@
         new Text("renewer"), null);
     ident.setSequenceNumber(1);
     Token<TimelineDelegationTokenIdentifier> collectorToken =
-        new Token<TimelineDelegationTokenIdentifier> (ident.getBytes(),
+        new Token<TimelineDelegationTokenIdentifier>(ident.getBytes(),
         new byte[0], TimelineDelegationTokenIdentifier.KIND_NAME,
         new Text(localAddr));
     org.apache.hadoop.yarn.api.records.Token token =
@@ -824,7 +823,7 @@
     // new token.
     ident.setSequenceNumber(100);
     Token<TimelineDelegationTokenIdentifier> collectorToken1 =
-        new Token<TimelineDelegationTokenIdentifier> (ident.getBytes(),
+        new Token<TimelineDelegationTokenIdentifier>(ident.getBytes(),
         new byte[0], TimelineDelegationTokenIdentifier.KIND_NAME,
         new Text(localAddr));
     token = org.apache.hadoop.yarn.api.records.Token.newInstance(
@@ -3579,15 +3578,15 @@
     }
   }
 
-  private static class MockSchedulerForTimelineCollector
+  private final static class MockSchedulerForTimelineCollector
       implements ApplicationMasterProtocol {
-    CollectorInfo collectorInfo;
+    private CollectorInfo collectorInfo;
 
-    public MockSchedulerForTimelineCollector(CollectorInfo info) {
+    private MockSchedulerForTimelineCollector(CollectorInfo info) {
       this.collectorInfo = info;
     }
 
-    void updateCollectorInfo(CollectorInfo info) {
+    private void updateCollectorInfo(CollectorInfo info) {
       collectorInfo = info;
     }
 
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/jobhistory/TaskAttemptUnsuccessfulCompletionEvent.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/jobhistory/TaskAttemptUnsuccessfulCompletionEvent.java
index 070e156..9afa093 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/jobhistory/TaskAttemptUnsuccessfulCompletionEvent.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/jobhistory/TaskAttemptUnsuccessfulCompletionEvent.java
@@ -62,7 +62,7 @@
   private long startTime;
   private static final Counters EMPTY_COUNTERS = new Counters();
 
-  /** 
+  /**
    * Create an event to record the unsuccessful completion of attempts.
    * @param id Attempt ID
    * @param taskType Type of the task
@@ -232,7 +232,7 @@
   public String getRackName() {
     return rackName == null ? null : rackName.toString();
   }
-  
+
   /** Gets the error string. */
   public String getError() { return error.toString(); }
   /**
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterConstants.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterConstants.java
index d96ad76..2afe52c 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterConstants.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterConstants.java
@@ -21,20 +21,21 @@
 /**
  * Constants for simple entity writers.
  */
-interface SimpleEntityWriterConstants {
+final class SimpleEntityWriterConstants {
+  private SimpleEntityWriterConstants() {}
   // constants for mtype = 1
-  String KBS_SENT = "kbs sent";
-  int KBS_SENT_DEFAULT = 1;
-  String TEST_TIMES = "testtimes";
-  int TEST_TIMES_DEFAULT = 100;
-  String TIMELINE_SERVICE_PERFORMANCE_RUN_ID =
+  static final String KBS_SENT = "kbs sent";
+  static final int KBS_SENT_DEFAULT = 1;
+  static final String TEST_TIMES = "testtimes";
+  static final int TEST_TIMES_DEFAULT = 100;
+  static final String TIMELINE_SERVICE_PERFORMANCE_RUN_ID =
       "timeline.server.performance.run.id";
 
   /**
    *  To ensure that the compression really gets exercised, generate a
    *  random alphanumeric fixed length payload.
    */
-  char[] ALPHA_NUMS = new char[] {'a', 'b', 'c', 'd', 'e', 'f',
+  static final char[] ALPHA_NUMS = new char[] {'a', 'b', 'c', 'd', 'e', 'f',
       'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
       's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D',
       'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV1.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV1.java
index 6d6151f..cf2da2b 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV1.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV1.java
@@ -39,8 +39,7 @@
    */
 class SimpleEntityWriterV1
     extends org.apache.hadoop.mapreduce.Mapper
-        <IntWritable, IntWritable, Writable, Writable>
-    implements SimpleEntityWriterConstants {
+        <IntWritable, IntWritable, Writable, Writable> {
   private static final Log LOG = LogFactory.getLog(SimpleEntityWriterV1.class);
 
   public void map(IntWritable key, IntWritable val, Context context)
@@ -48,10 +47,12 @@
     TimelineClient tlc = TimelineClient.createTimelineClient();
     Configuration conf = context.getConfiguration();
 
-    final int kbs = conf.getInt(KBS_SENT, KBS_SENT_DEFAULT);
+    final int kbs = conf.getInt(SimpleEntityWriterConstants.KBS_SENT,
+        SimpleEntityWriterConstants.KBS_SENT_DEFAULT);
 
     long totalTime = 0;
-    final int testtimes = conf.getInt(TEST_TIMES, TEST_TIMES_DEFAULT);
+    final int testtimes = conf.getInt(SimpleEntityWriterConstants.TEST_TIMES,
+        SimpleEntityWriterConstants.TEST_TIMES_DEFAULT);
     final Random rand = new Random();
     final TaskAttemptID taskAttemptId = context.getTaskAttemptID();
     final char[] payLoad = new char[kbs * 1024];
@@ -60,8 +61,8 @@
       // Generate a fixed length random payload
       for (int xx = 0; xx < kbs * 1024; xx++) {
         int alphaNumIdx =
-            rand.nextInt(ALPHA_NUMS.length);
-        payLoad[xx] = ALPHA_NUMS[alphaNumIdx];
+            rand.nextInt(SimpleEntityWriterConstants.ALPHA_NUMS.length);
+        payLoad[xx] = SimpleEntityWriterConstants.ALPHA_NUMS[alphaNumIdx];
       }
       String entId = taskAttemptId + "_" + Integer.toString(i);
       final TimelineEntity entity = new TimelineEntity();
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV2.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV2.java
index d66deb0..4612f9c 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV2.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/SimpleEntityWriterV2.java
@@ -40,8 +40,7 @@
  * Adds simple entities with random string payload, events, metrics, and
  * configuration.
  */
-class SimpleEntityWriterV2 extends EntityWriterV2
-    implements SimpleEntityWriterConstants {
+class SimpleEntityWriterV2 extends EntityWriterV2 {
   private static final Log LOG = LogFactory.getLog(SimpleEntityWriterV2.class);
 
   protected void writeEntities(Configuration tlConf,
@@ -49,7 +48,8 @@
     Configuration conf = context.getConfiguration();
     // simulate the app id with the task id
     int taskId = context.getTaskAttemptID().getTaskID().getId();
-    long timestamp = conf.getLong(TIMELINE_SERVICE_PERFORMANCE_RUN_ID, 0);
+    long timestamp = conf.getLong(
+        SimpleEntityWriterConstants.TIMELINE_SERVICE_PERFORMANCE_RUN_ID, 0);
     ApplicationId appId = ApplicationId.newInstance(timestamp, taskId);
 
     // create the app level timeline collector
@@ -66,10 +66,12 @@
       tlContext.setFlowRunId(timestamp);
       tlContext.setUserId(context.getUser());
 
-      final int kbs = conf.getInt(KBS_SENT, KBS_SENT_DEFAULT);
+      final int kbs = conf.getInt(SimpleEntityWriterConstants.KBS_SENT,
+          SimpleEntityWriterConstants.KBS_SENT_DEFAULT);
 
       long totalTime = 0;
-      final int testtimes = conf.getInt(TEST_TIMES, TEST_TIMES_DEFAULT);
+      final int testtimes = conf.getInt(SimpleEntityWriterConstants.TEST_TIMES,
+          SimpleEntityWriterConstants.TEST_TIMES_DEFAULT);
       final Random rand = new Random();
       final TaskAttemptID taskAttemptId = context.getTaskAttemptID();
       final char[] payLoad = new char[kbs * 1024];
@@ -78,8 +80,8 @@
         // Generate a fixed length random payload
         for (int xx = 0; xx < kbs * 1024; xx++) {
           int alphaNumIdx =
-              rand.nextInt(ALPHA_NUMS.length);
-          payLoad[xx] = ALPHA_NUMS[alphaNumIdx];
+              rand.nextInt(SimpleEntityWriterConstants.ALPHA_NUMS.length);
+          payLoad[xx] = SimpleEntityWriterConstants.ALPHA_NUMS[alphaNumIdx];
         }
         String entId = taskAttemptId + "_" + Integer.toString(i);
         final TimelineEntity entity = new TimelineEntity();
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineMetric.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineMetric.java
index 3244bc37..a6a3fda 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineMetric.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineMetric.java
@@ -27,6 +27,9 @@
 
 import org.junit.Test;
 
+/**
+ * Tests {@link TimelineMetric} operations such as aggregation.
+ */
 public class TestTimelineMetric {
 
   @Test
@@ -86,15 +89,4 @@
     m.setValues(metricValues);
     return m;
   }
-
-  private static TimelineMetric getTimeSeriesMetric(String id,
-      TimelineMetricOperation op, Map<Long, Number> metricValues) {
-    TimelineMetric m = new TimelineMetric();
-    m.setId(id);
-    m.setType(Type.TIME_SERIES);
-    m.setRealtimeAggregationOp(op);
-    m.setValues(metricValues);
-    return m;
-  }
-
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/TimelineV2Client.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/TimelineV2Client.java
index da81a91..423c059 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/TimelineV2Client.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/TimelineV2Client.java
@@ -24,7 +24,6 @@
 import org.apache.hadoop.service.CompositeService;
 import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.api.records.CollectorInfo;
-import org.apache.hadoop.yarn.api.records.Token;
 import org.apache.hadoop.yarn.api.records.timelineservice.TimelineEntity;
 import org.apache.hadoop.yarn.client.api.impl.TimelineV2ClientImpl;
 import org.apache.hadoop.yarn.exceptions.YarnException;
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/impl/TimelineConnector.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/impl/TimelineConnector.java
index 9d084d7..188371e 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/impl/TimelineConnector.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/impl/TimelineConnector.java
@@ -131,8 +131,8 @@
     }
   }
 
-  private static final ConnectionConfigurator DEFAULT_TIMEOUT_CONN_CONFIGURATOR
-    = new ConnectionConfigurator() {
+  private static final ConnectionConfigurator
+      DEFAULT_TIMEOUT_CONN_CONFIGURATOR = new ConnectionConfigurator() {
         @Override
         public HttpURLConnection configure(HttpURLConnection conn)
             throws IOException {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
index 8bec3a7..14acebd 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
@@ -3218,7 +3218,7 @@
     <name>yarn.app.attempt.diagnostics.limit.kc</name>
     <value>64</value>
   </property>
-  
+
   <property>
     <description>
       Flag to enable cross-origin (CORS) support for timeline service v1.x or
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineServiceRecords.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineServiceRecords.java
index 221969b..04bf4294 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineServiceRecords.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/records/timelineservice/TestTimelineServiceRecords.java
@@ -34,7 +34,9 @@
 import java.util.Iterator;
 import java.util.Map;
 
-
+/**
+ * Tests timeline service API records.
+ */
 public class TestTimelineServiceRecords {
   private static final Log LOG =
       LogFactory.getLog(TestTimelineServiceRecords.class);
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClient.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClient.java
index d7e3ce4..7876074 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClient.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClient.java
@@ -426,15 +426,14 @@
             new TimelineConnector(true, authUgi, doAsUser, token) {
               @Override
               public TimelineClientRetryOp
-                createRetryOpForOperateDelegationToken(
+                  createRetryOpForOperateDelegationToken(
                   final PrivilegedExceptionAction<?> action)
                   throws IOException {
                 TimelineClientRetryOpForOperateDelegationToken op =
                     spy(new TimelineClientRetryOpForOperateDelegationToken(
                         UserGroupInformation.getCurrentUser(), action));
-                doThrow(
-                    new SocketTimeoutException("Test socketTimeoutException"))
-                        .when(op).run();
+                doThrow(new SocketTimeoutException(
+                    "Test socketTimeoutException")).when(op).run();
                 return op;
               }
             };
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClientV2Impl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClientV2Impl.java
index 95595a9..b1e490d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClientV2Impl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestTimelineClientV2Impl.java
@@ -49,6 +49,9 @@
 import org.junit.Test;
 import org.junit.rules.TestName;
 
+/**
+ * Tests {@link TimelineV2ClientImpl}.
+ */
 public class TestTimelineClientV2Impl {
   private static final Log LOG =
       LogFactory.getLog(TestTimelineClientV2Impl.class);
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestTimelineServiceHelper.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestTimelineServiceHelper.java
index d3d815b..7dffc20 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestTimelineServiceHelper.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestTimelineServiceHelper.java
@@ -26,6 +26,9 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+/**
+ * Tests utility methods in {@link TimelineServiceHelper}.
+ */
 public class TestTimelineServiceHelper {
 
   @Test
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/CollectorNodemanagerProtocolPB.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/CollectorNodemanagerProtocolPB.java
index 24f7c3d..9529ddd 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/CollectorNodemanagerProtocolPB.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/CollectorNodemanagerProtocolPB.java
@@ -22,6 +22,9 @@
 import org.apache.hadoop.ipc.ProtocolInfo;
 import org.apache.hadoop.yarn.proto.CollectorNodemanagerProtocol.CollectorNodemanagerProtocolService;
 
+/**
+ * Collector nodemanager protocol service implementation.
+ */
 @Private
 @Unstable
 @ProtocolInfo(
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/CollectorNodemanagerProtocolPBClientImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/CollectorNodemanagerProtocolPBClientImpl.java
index bc50ac5..a4f18d2 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/CollectorNodemanagerProtocolPBClientImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/CollectorNodemanagerProtocolPBClientImpl.java
@@ -45,6 +45,9 @@
 
 import com.google.protobuf.ServiceException;
 
+/**
+ * Client implementation of {@link CollectorNodemanagerProtocol}.
+ */
 public class CollectorNodemanagerProtocolPBClientImpl implements
     CollectorNodemanagerProtocol, Closeable {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/package-info.java
similarity index 81%
copy from hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
copy to hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/package-info.java
index 74c81a7..fad9a71 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/client/package-info.java
@@ -1,4 +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
@@ -16,8 +16,8 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.server.timelineservice.collector;
-
-
-public class TestAppLevelTimelineCollector {
-}
+/**
+ * Contains protocol client implementations used to communicate with different
+ * YARN server components.
+ */
+package org.apache.hadoop.yarn.server.api.impl.pb.client;
\ No newline at end of file
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/service/CollectorNodemanagerProtocolPBServiceImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/service/CollectorNodemanagerProtocolPBServiceImpl.java
index 7b93a68..cbe8137 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/service/CollectorNodemanagerProtocolPBServiceImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/impl/pb/service/CollectorNodemanagerProtocolPBServiceImpl.java
@@ -36,6 +36,9 @@
 import com.google.protobuf.RpcController;
 import com.google.protobuf.ServiceException;
 
+/**
+ * Service implementation of CollectorNodemanagerProtocol.
+ */
 public class CollectorNodemanagerProtocolPBServiceImpl implements
     CollectorNodemanagerProtocolPB {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/package-info.java
similarity index 83%
copy from hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
copy to hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/package-info.java
index 74c81a7..52f8df4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/package-info.java
@@ -1,4 +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
@@ -16,8 +16,8 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.server.timelineservice.collector;
-
-
-public class TestAppLevelTimelineCollector {
-}
+/**
+ * Contains interfaces which define the protocols to communicate with different
+ * YARN server components.
+ */
+package org.apache.hadoop.yarn.server.api;
\ No newline at end of file
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextRequest.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextRequest.java
index 604a40b..321c41d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextRequest.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextRequest.java
@@ -21,6 +21,11 @@
 import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.util.Records;
 
+/**
+ * GetTimelineCollectorContextRequest invoked by collector to get the context
+ * information from Nodemanager. The context information includes user, flow and
+ * flow run ID and is associated with every incoming put-entity request.
+ */
 public abstract class GetTimelineCollectorContextRequest {
 
   public static GetTimelineCollectorContextRequest newInstance(
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextResponse.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextResponse.java
index bd5c11ee..8a424d9 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextResponse.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/GetTimelineCollectorContextResponse.java
@@ -20,6 +20,12 @@
 
 import org.apache.hadoop.yarn.util.Records;
 
+/**
+ * GetTimelineCollectorContextResponse sent in response of
+ * GetTimelineCollectorContextRequest invoked by collector. The response
+ * includes user, flow name, flow version and flow run ID. This is then
+ * associated by collector with every incoming put-entity request.
+ */
 public abstract class GetTimelineCollectorContextResponse {
 
   public static GetTimelineCollectorContextResponse newInstance(
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoRequest.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoRequest.java
index a4c1a38..2634f24 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoRequest.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoRequest.java
@@ -26,6 +26,12 @@
 import org.apache.hadoop.yarn.server.api.records.AppCollectorData;
 import org.apache.hadoop.yarn.util.Records;
 
+/**
+ * Request used to report new collector info from timeline collector manager
+ * whenever a collector is launched.
+ * The request contains a list of collector data, with each collector data
+ * object represented by {@link AppCollectorData}.
+ */
 @Private
 public abstract class ReportNewCollectorInfoRequest {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoResponse.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoResponse.java
index 4157c47..aa95122 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoResponse.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/ReportNewCollectorInfoResponse.java
@@ -20,6 +20,9 @@
 import org.apache.hadoop.classification.InterfaceAudience.Private;
 import org.apache.hadoop.yarn.util.Records;
 
+/**
+ * Response to {@link ReportNewCollectorInfoRequest}.
+ */
 public abstract class ReportNewCollectorInfoResponse {
 
   @Private
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextRequestPBImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextRequestPBImpl.java
index 7014388..4703362 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextRequestPBImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextRequestPBImpl.java
@@ -26,6 +26,10 @@
 import org.apache.hadoop.yarn.proto.YarnServerCommonServiceProtos.GetTimelineCollectorContextRequestProto;
 import org.apache.hadoop.yarn.server.api.protocolrecords.GetTimelineCollectorContextRequest;
 
+/**
+ * Protocol buffer based implementation of
+ * {@link GetTimelineCollectorContextRequest}.
+ */
 public class GetTimelineCollectorContextRequestPBImpl extends
     GetTimelineCollectorContextRequest {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextResponsePBImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextResponsePBImpl.java
index 151b036..6ac1f05 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextResponsePBImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/GetTimelineCollectorContextResponsePBImpl.java
@@ -23,6 +23,10 @@
 import org.apache.hadoop.yarn.proto.YarnServerCommonServiceProtos.GetTimelineCollectorContextResponseProto;
 import org.apache.hadoop.yarn.server.api.protocolrecords.GetTimelineCollectorContextResponse;
 
+/**
+ * Protocol buffer based implementation of
+ * {@link GetTimelineCollectorContextResponse}.
+ */
 public class GetTimelineCollectorContextResponsePBImpl extends
     GetTimelineCollectorContextResponse {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoRequestPBImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoRequestPBImpl.java
index 5ffc3a2..e915beb8 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoRequestPBImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoRequestPBImpl.java
@@ -27,6 +27,10 @@
 import org.apache.hadoop.yarn.proto.YarnServerCommonServiceProtos.ReportNewCollectorInfoRequestProtoOrBuilder;
 import org.apache.hadoop.yarn.server.api.protocolrecords.ReportNewCollectorInfoRequest;
 
+/**
+ * Protocol buffer based implementation of
+ * {@link ReportNewCollectorInfoRequest}.
+ */
 public class ReportNewCollectorInfoRequestPBImpl extends
     ReportNewCollectorInfoRequest {
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoResponsePBImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoResponsePBImpl.java
index 5f2a10a..782d445 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoResponsePBImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/ReportNewCollectorInfoResponsePBImpl.java
@@ -24,6 +24,10 @@
 
 import com.google.protobuf.TextFormat;
 
+/**
+ * Protocol buffer based implementation of
+ * {@link ReportNewCollectorInfoResponse}.
+ */
 @Private
 @Unstable
 public class ReportNewCollectorInfoResponsePBImpl extends
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/package-info.java
similarity index 84%
rename from hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
rename to hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/package-info.java
index 74c81a7..843f24b 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestAppLevelTimelineCollector.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/protocolrecords/impl/pb/package-info.java
@@ -1,4 +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
@@ -16,8 +16,7 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.server.timelineservice.collector;
-
-
-public class TestAppLevelTimelineCollector {
-}
+/**
+ * Contains protocol record implementations for YARN server protocols.
+ */
+package org.apache.hadoop.yarn.server.api.protocolrecords.impl.pb;
\ No newline at end of file
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/AppCollectorData.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/AppCollectorData.java
index 5266dca..2e1dc9a 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/AppCollectorData.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/AppCollectorData.java
@@ -24,7 +24,10 @@
 import org.apache.hadoop.yarn.api.records.Token;
 import org.apache.hadoop.yarn.util.Records;
 
-
+/**
+ * Collector data associated with an app collector. Includes app Id, collector
+ * address, RM identifier, version and collector token.
+ */
 @Private
 @InterfaceStability.Unstable
 public abstract class AppCollectorData {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/impl/pb/AppCollectorDataPBImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/impl/pb/AppCollectorDataPBImpl.java
index c08e9ca..f87f7f6 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/impl/pb/AppCollectorDataPBImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/records/impl/pb/AppCollectorDataPBImpl.java
@@ -30,6 +30,9 @@
 
 import com.google.protobuf.TextFormat;
 
+/**
+ * Protocol Buffer based implementation of {@link AppCollectorData}.
+ */
 @Private
 @Unstable
 public class AppCollectorDataPBImpl extends AppCollectorData {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/timeline/security/TimelineAuthenticationFilterInitializer.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/timeline/security/TimelineAuthenticationFilterInitializer.java
index 06f9868e..eb557a9 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/timeline/security/TimelineAuthenticationFilterInitializer.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/timeline/security/TimelineAuthenticationFilterInitializer.java
@@ -53,7 +53,8 @@
   /**
    * The configuration prefix of timeline HTTP authentication.
    */
-  public static final String PREFIX = "yarn.timeline-service.http-authentication.";
+  public static final String PREFIX =
+      "yarn.timeline-service.http-authentication.";
 
   @VisibleForTesting
   Map<String, String> filterConfig;
@@ -104,7 +105,7 @@
   }
 
   /**
-   * Initializes {@link TimelineAuthenticationFilter}
+   * Initializes {@link TimelineAuthenticationFilter}.
    * <p>
    * Propagates to {@link TimelineAuthenticationFilter} configuration all YARN
    * configuration properties prefixed with {@value #PREFIX}
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/TestRPC.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/TestRPC.java
index 82dfaea..5fbf412 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/TestRPC.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/TestRPC.java
@@ -84,6 +84,9 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+/**
+ * Tests RPC communication for different YARN server protocols.
+ */
 public class TestRPC {
 
   private static final String EXCEPTION_MSG = "test error";
@@ -320,7 +323,8 @@
     Assert.assertEquals(ContainerState.RUNNING, statuses.get(0).getState());
   }
 
-  public class DummyContainerManager implements ContainerManagementProtocol {
+  private static class DummyContainerManager
+      implements ContainerManagementProtocol {
 
     private List<ContainerStatus> statuses = new ArrayList<ContainerStatus>();
 
@@ -448,7 +452,7 @@
 
   // A dummy implementation for CollectorNodemanagerProtocol for test purpose,
   // it only can accept one appID, collectorAddr pair or throw exceptions
-  public class DummyNMCollectorService
+  private static class DummyNMCollectorService
       implements CollectorNodemanagerProtocol {
 
     @Override
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/server/timeline/security/TestTimelineAuthenticationFilterInitializer.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/server/timeline/security/TestTimelineAuthenticationFilterInitializer.java
index 430911e..44f63ea 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/server/timeline/security/TestTimelineAuthenticationFilterInitializer.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/server/timeline/security/TestTimelineAuthenticationFilterInitializer.java
@@ -27,7 +27,9 @@
 import org.junit.Test;
 import org.mockito.Mockito;
 
-
+/**
+ * Tests {@link TimelineAuthenticationFilterInitializer}.
+ */
 public class TestTimelineAuthenticationFilterInitializer {
 
   @Test
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/ContainerManagerImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/ContainerManagerImpl.java
index 4bdea32..ffd1a33 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/ContainerManagerImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/ContainerManagerImpl.java
@@ -429,6 +429,7 @@
     app.handle(new ApplicationInitEvent(appId, acls, logAggregationContext));
   }
 
+  @SuppressWarnings("unchecked")
   private void recoverContainer(RecoveredContainerState rcs)
       throws IOException {
     StartContainerRequest req = rcs.getStartRequest();
@@ -1735,6 +1736,7 @@
    * @param reInitLaunchContext Target Launch Context.
    * @throws YarnException Yarn Exception.
    */
+  @SuppressWarnings("unchecked")
   public void reInitializeContainer(ContainerId containerId,
       ContainerLaunchContext reInitLaunchContext, boolean autoCommit)
       throws YarnException {
@@ -1762,6 +1764,7 @@
    * @return Rollback Response.
    * @throws YarnException Yarn Exception.
    */
+  @SuppressWarnings("unchecked")
   @Override
   public RollbackResponse rollbackLastReInitialization(ContainerId containerId)
       throws YarnException {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java
index 1174734..a7ea8cc 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java
@@ -85,6 +85,9 @@
   private static final long UNKNOWN_MEMORY_LIMIT = -1L;
   private int nodeCpuPercentageForYARN;
 
+  /**
+   * Identifies the type of container metric to be published.
+   */
   @Private
   public static enum ContainerMetric {
     CPU, MEMORY
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/security/authorize/NMPolicyProvider.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/security/authorize/NMPolicyProvider.java
index cc668f7..1c831d7 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/security/authorize/NMPolicyProvider.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/security/authorize/NMPolicyProvider.java
@@ -33,21 +33,22 @@
 @InterfaceStability.Unstable
 public class NMPolicyProvider extends PolicyProvider {
   
-  private static final Service[] nodeManagerServices = 
+  private static final Service[] NODE_MANAGER_SERVICES =
       new Service[] {
-    new Service(
-        YarnConfiguration.YARN_SECURITY_SERVICE_AUTHORIZATION_CONTAINER_MANAGEMENT_PROTOCOL, 
-        ContainerManagementProtocolPB.class),
-    new Service(YarnConfiguration.YARN_SECURITY_SERVICE_AUTHORIZATION_RESOURCE_LOCALIZER, 
-        LocalizationProtocolPB.class),
-    new Service(YarnConfiguration.
-        YARN_SECURITY_SERVICE_AUTHORIZATION_COLLECTOR_NODEMANAGER_PROTOCOL,
+          new Service(YarnConfiguration.
+            YARN_SECURITY_SERVICE_AUTHORIZATION_CONTAINER_MANAGEMENT_PROTOCOL,
+            ContainerManagementProtocolPB.class),
+          new Service(YarnConfiguration.
+            YARN_SECURITY_SERVICE_AUTHORIZATION_RESOURCE_LOCALIZER,
+            LocalizationProtocolPB.class),
+          new Service(YarnConfiguration.
+            YARN_SECURITY_SERVICE_AUTHORIZATION_COLLECTOR_NODEMANAGER_PROTOCOL,
             CollectorNodemanagerProtocolPB.class)
-  };
+      };
 
   @Override
   public Service[] getServices() {
-    return nodeManagerServices;
+    return NODE_MANAGER_SERVICES;
   }
 
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/timelineservice/TestNMTimelinePublisher.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/timelineservice/TestNMTimelinePublisher.java
index 0b8eaa9..50f9e8b 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/timelineservice/TestNMTimelinePublisher.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/timelineservice/TestNMTimelinePublisher.java
@@ -18,6 +18,9 @@
 
 package org.apache.hadoop.yarn.server.nodemanager.timelineservice;
 
+/**
+ * Tests publishing of entities from NM to ATSv2.
+ */
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.mockito.Mockito.mock;
@@ -43,6 +46,9 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+/**
+ * Tests {@link NMTimelinePublisher}.
+ */
 public class TestNMTimelinePublisher {
   private static final String MEMORY_ID = "MEMORY";
   private static final String CPU_ID = "CPU";
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ApplicationMasterService.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ApplicationMasterService.java
index 988ad9f..90c42be 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ApplicationMasterService.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ApplicationMasterService.java
@@ -45,7 +45,6 @@
 import org.apache.hadoop.yarn.api.protocolrecords.FinishApplicationMasterResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.RegisterApplicationMasterRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.RegisterApplicationMasterResponse;
-import org.apache.hadoop.yarn.api.records.CollectorInfo;
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
 import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.api.records.ApplicationSubmissionContext;
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/DefaultAMSProcessor.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/DefaultAMSProcessor.java
index c8cff80..d5444b4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/DefaultAMSProcessor.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/DefaultAMSProcessor.java
@@ -55,7 +55,6 @@
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.factories.RecordFactory;
 import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
-import org.apache.hadoop.yarn.server.api.records.AppCollectorData;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/TestSystemMetricsPublisherForV2.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/TestSystemMetricsPublisherForV2.java
index c34307b..b18a702 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/TestSystemMetricsPublisherForV2.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/TestSystemMetricsPublisherForV2.java
@@ -75,6 +75,9 @@
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+/**
+ * Tests publishing of entities and metrics from RM to ATSv2.
+ */
 public class TestSystemMetricsPublisherForV2 {
 
   /**
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/TestRMNMSecretKeys.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/TestRMNMSecretKeys.java
index 56872d3..de3b0d7 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/TestRMNMSecretKeys.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/TestRMNMSecretKeys.java
@@ -67,13 +67,13 @@
   }
 
   private static void writeFile(String content, File file) throws IOException {
-      FileOutputStream outputStream = new FileOutputStream(file);
-      FileChannel fc = outputStream.getChannel();
+    FileOutputStream outputStream = new FileOutputStream(file);
+    FileChannel fc = outputStream.getChannel();
 
-      ByteBuffer buffer =
-          ByteBuffer.wrap(content.getBytes(StandardCharsets.UTF_8));
-      fc.write(buffer);
-      outputStream.close();
+    ByteBuffer buffer =
+        ByteBuffer.wrap(content.getBytes(StandardCharsets.UTF_8));
+    fc.write(buffer);
+    outputStream.close();
   }
 
   @AfterClass
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/TestTimelineServiceClientIntegration.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/TestTimelineServiceClientIntegration.java
index 6a5ef55..8df2fcb 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/TestTimelineServiceClientIntegration.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/TestTimelineServiceClientIntegration.java
@@ -58,6 +58,9 @@
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+/**
+ * Tests timeline client integration with collector service.
+ */
 public class TestTimelineServiceClientIntegration {
   private static final String ROOT_DIR = new File("target",
       TestTimelineServiceClientIntegration.class.getSimpleName()).
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesHBaseStorage.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesHBaseStorage.java
index 4bbab25..4260968 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesHBaseStorage.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase-tests/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesHBaseStorage.java
@@ -64,7 +64,7 @@
 import com.sun.jersey.api.client.GenericType;
 
 /**
- * Test TimelineReder Web Service REST API's.
+ * Test TimelineReder Web Service REST API's using HBase storage.
  */
 public class TestTimelineReaderWebServicesHBaseStorage
     extends AbstractTimelineReaderHBaseTestBase {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/common/TestSeparator.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/common/TestSeparator.java
index 7d37206..30046f1 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/common/TestSeparator.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/common/TestSeparator.java
@@ -30,6 +30,10 @@
 
 import com.google.common.collect.Iterables;
 
+/**
+ * Tests the encoding and decoding of separators. Typically used to separate
+ * different segments in HBase row key.
+ */
 public class TestSeparator {
 
   private static String villain = "Dr. Heinz Doofenshmirtz";
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/reader/security/TimelineReaderAuthenticationFilterInitializer.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/reader/security/TimelineReaderAuthenticationFilterInitializer.java
index e0e1f4d..e1c93be 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/reader/security/TimelineReaderAuthenticationFilterInitializer.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/reader/security/TimelineReaderAuthenticationFilterInitializer.java
@@ -36,7 +36,7 @@
    * <p>
    * Propagates to {@link AuthenticationWithProxyUserFilter} configuration all
    * YARN configuration properties prefixed with
-   * {@value TimelineAuthenticationFilterInitializer#PREFIX}.
+   * {@link TimelineAuthenticationFilterInitializer#PREFIX}.
    *
    * @param container
    *          The filter container
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/TimelineReader.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/TimelineReader.java
index 1e77155..16d623a 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/TimelineReader.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/TimelineReader.java
@@ -125,7 +125,7 @@
    *    <li><b>flowRunId</b> - Context flow run id.</li>
    *    <li><b>appId</b> - Context app id.</li>
    *    </ul>
-   *    Although entityIdPrefix and entityId are also part of context, 
+   *    Although entityIdPrefix and entityId are also part of context,
    *    it has no meaning for getEntities.<br>
    *    Fields in context which are mandatory depends on entity type. Entity
    *    type is always mandatory. In addition to entity type, below is the list
@@ -161,7 +161,7 @@
    *    {@link TimelineDataToRetrieve} for details.
    * @return A set of <cite>TimelineEntity</cite> instances of the given entity
    *    type in the given context scope which matches the given predicates
-   *    ordered by enitityIdPrefix(for generic entities only). 
+   *    ordered by enitityIdPrefix(for generic entities only).
    *    Each entity will only contain
    *    the metadata(id, type , idPrefix and created time) plus the given
    *    fields to retrieve.
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestNMTimelineCollectorManager.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestNMTimelineCollectorManager.java
index af9acce..e076395 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestNMTimelineCollectorManager.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestNMTimelineCollectorManager.java
@@ -51,6 +51,9 @@
 import org.junit.Before;
 import org.junit.Test;
 
+/**
+ * Tests node level timeline collector manager.
+ */
 public class TestNMTimelineCollectorManager {
   private NodeTimelineCollectorManager collectorManager;
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestPerNodeTimelineCollectorsAuxService.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestPerNodeTimelineCollectorsAuxService.java
index cb9ced0..a1d4aa9 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestPerNodeTimelineCollectorsAuxService.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestPerNodeTimelineCollectorsAuxService.java
@@ -49,6 +49,10 @@
 import org.junit.After;
 import org.junit.Test;
 
+/**
+ * Tests the NodeManager auxiliary service started for node level timeline
+ * collector.
+ */
 public class TestPerNodeTimelineCollectorsAuxService {
   private ApplicationAttemptId appAttemptId;
   private PerNodeTimelineCollectorsAuxService auxService;
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestTimelineCollector.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestTimelineCollector.java
index ec45428..7c4d989 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestTimelineCollector.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/collector/TestTimelineCollector.java
@@ -46,6 +46,9 @@
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
+/**
+ * Tests functionality of timeline collector.
+ */
 public class TestTimelineCollector {
 
   private TimelineEntities generateTestEntities(int groups, int entities) {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderServer.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderServer.java
index bb96f37..2d470a5 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderServer.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderServer.java
@@ -28,6 +28,9 @@
 import org.apache.hadoop.yarn.server.timelineservice.storage.TimelineReader;
 import org.junit.Test;
 
+/**
+ * Tests {@link TimelineReaderServer} start and stop.
+ */
 public class TestTimelineReaderServer {
 
   @Test(timeout = 60000)
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderUtils.java
index bc5eb9c..b8ff951 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderUtils.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderUtils.java
@@ -26,6 +26,9 @@
 
 import org.junit.Test;
 
+/**
+ * Tests helper methods in {@link TimelineReaderUtils}.
+ */
 public class TestTimelineReaderUtils {
 
   @Test
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServices.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServices.java
index 915d2f2..476959c 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServices.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServices.java
@@ -59,6 +59,9 @@
 import com.sun.jersey.client.urlconnection.HttpURLConnectionFactory;
 import com.sun.jersey.client.urlconnection.URLConnectionClientHandler;
 
+/**
+ * Test TimelineReder Web Service REST API's using filesystem storage.
+ */
 public class TestTimelineReaderWebServices {
 
   private static final String ROOT_DIR = new File("target",
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesUtils.java
index b2837c2..13e129e 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesUtils.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineReaderWebServicesUtils.java
@@ -35,6 +35,9 @@
 
 import com.google.common.collect.Sets;
 
+/**
+ * Tests helper methods in {@link TimelineReaderWebServicesUtils}.
+ */
 public class TestTimelineReaderWebServicesUtils {
   private static void verifyFilterList(String expr, TimelineFilterList list,
       TimelineFilterList expectedList) throws Exception {
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineUIDConverter.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineUIDConverter.java
index 12b3fc0..a720a2d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineUIDConverter.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/reader/TestTimelineUIDConverter.java
@@ -24,6 +24,9 @@
 
 import org.junit.Test;
 
+/**
+ * Tests Timeline UIDs' encoding and decoding.
+ */
 public class TestTimelineUIDConverter {
 
   @Test
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineReaderImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineReaderImpl.java
index 46873ab..a031a87 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineReaderImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineReaderImpl.java
@@ -59,6 +59,9 @@
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+/**
+ * Tests filesystem implemetation for timelineservice reader.
+ */
 public class TestFileSystemTimelineReaderImpl {
 
   private static final String ROOT_DIR = new File("target",
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineWriterImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineWriterImpl.java
index bb9f54f..6466194 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineWriterImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/test/java/org/apache/hadoop/yarn/server/timelineservice/storage/TestFileSystemTimelineWriterImpl.java
@@ -42,6 +42,9 @@
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 
+/**
+ * Tests filesystem implemetation for timelineservice writer.
+ */
 public class TestFileSystemTimelineWriterImpl {
   @Rule
   public TemporaryFolder tmpFolder = new TemporaryFolder();