HADOOP-11369. Fix new findbugs warnings in hadoop-mapreduce-client, non-core directories. Contributed by Li Lu.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -536,6 +536,9 @@ Release 2.7.0 - UNRELEASED
 
     HADOOP-11367. Fix warnings from findbugs 3.0 in hadoop-streaming. (Li Lu via wheat9)
 
+    HADOOP-11369. Fix new findbugs warnings in hadoop-mapreduce-client,
+    non-core directories. (Li Lu via wheat9)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/jobhistory/JobHistoryEventHandler.java

@@ -870,8 +870,7 @@ public class JobHistoryEventHandler extends AbstractService
         TaskAttemptStartedEvent tase = (TaskAttemptStartedEvent) event;
         tEvent.addEventInfo("TASK_TYPE", tase.getTaskType().toString());
         tEvent.addEventInfo("TASK_ATTEMPT_ID",
-            tase.getTaskAttemptId().toString() == null ?
-            "" : tase.getTaskAttemptId().toString());
+            tase.getTaskAttemptId().toString());
         tEvent.addEventInfo("START_TIME", tase.getStartTime());
         tEvent.addEventInfo("HTTP_PORT", tase.getHttpPort());
         tEvent.addEventInfo("TRACKER_NAME", tase.getTrackerName());

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/rm/RMCommunicator.java

@@ -76,7 +76,6 @@ public abstract class RMCommunicator extends AbstractService
   protected EventHandler eventHandler;
   protected ApplicationMasterProtocol scheduler;
   private final ClientService clientService;
-  protected int lastResponseID;
   private Resource maxContainerCapability;
   protected Map<ApplicationAccessType, String> applicationACLs;
   private volatile long lastHeartbeatTime;

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryFileManager.java

@@ -848,7 +848,7 @@ public class HistoryFileManager extends AbstractService {
             }
           });
         }
-      } else if (old != null && !old.isMovePending()) {
+      } else if (!old.isMovePending()) {
         //This is a duplicate so just delete it
         if (LOG.isDebugEnabled()) {
           LOG.debug("Duplicate: deleting");