Merge -r 1173455:1173456 from trunk to branch-0.23 to fix MAPREDUCE-2998.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1173457 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -1343,6 +1343,9 @@ Release 0.23.0 - Unreleased
     MAPREDUCE-3036. Fixed metrics for reserved resources in CS. (Robert Evans
     via acmurthy)
 
+    MAPREDUCE-2998. Fixed a bug in TaskAttemptImpl which caused it to fork
+    bin/mapred too many times. (vinodkv via acmurthy)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java

@@ -153,7 +153,7 @@ public abstract class TaskAttemptImpl implements
   private Token<JobTokenIdentifier> jobToken;
   private static AtomicBoolean initialClasspathFlag = new AtomicBoolean();
   private static String initialClasspath = null;
-  private final Object classpathLock = new Object();
+  private static final Object classpathLock = new Object();
   private long launchTime;
   private long finishTime;
   private WrappedProgressSplitsBlock progressSplitBlock;