MAPREDUCE-5414. TestTaskAttempt fails in JDK7 with NPE. Contributed by Nemon Lou.
svn merge --ignore-ancestry -c 1520964 ../../trunk



git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520965 13f79535-47bb-0310-9956-ffa450edef68