Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  AbstractElasticIndex: Add helper method to invoke base64 decode
  Elasticsearch: Don't use JsonElement.toString
  ElasticChangeIndex: Consistently use static imported Base64.decodeBase64
  MergeValidationListener: Add missing Javadoc

Change-Id: I1e676fca98ec50e3bf7abd418d29532aa4d0c2ae
tree: 454a6127e5854ee2dd62508b43e2187c16574b00
  1. java/
  2. javatests/