Merge branch 'stable-3.1' into stable-3.2

* stable-3.1:
  Use volatile and AtomicIntegers to be thread safe

Change-Id: I923730a525fbffb4c304ab0d23b088f5e8bfa307
tree: 1c0db7875775b142dc7c25765c0817be65c943aa
  1. .settings/
  2. src/
  3. .gitignore
  4. .mailmap
  5. BUILD
  6. LICENSE