YARN-2917. Fixed potential deadlock when system.exit is called in AsyncDispatcher. Contributed by Rohith Sharmaks
(cherry picked from commit 614b6afea450ebb897fbb2519c6f02e13b9bd12d)
HDFS-7515. Fix new findbugs warnings in hadoop-hdfs. Contributed by Haohui Mai.
HADOOP-11211. mapreduce.job.classloader.system.classes semantics should be order-independent. (Yitong Zhou via gera)

(cherry picked from commit 0bcea111e5daa9a4315346cf6919a4cfc8d90e0d)