svn merge -c 1303634 FIXES: HADOOP-8157. Fix race condition in Configuration that could cause spurious ClassNotFoundExceptions after a GC. Contributed by Todd Lipcon.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1434412 13f79535-47bb-0310-9956-ffa450edef68