Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  ElasticContainer: Use 7.0.0-alpha2

Change-Id: I3ac909ab9e19da41e2c2b03b966f4abc507c3c54
tree: 7b74b7eac5bf31fe5e060224a21d33e9a0585870
  1. java/
  2. javatests/