svn merge -c 1618080 FIXES: MAPREDUCE-5878. some standard JDK APIs are not part of system classes defaults. Contributed by Sangjin Lee


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1618081 13f79535-47bb-0310-9956-ffa450edef68