Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Elasticsearch: Update elasticsearch-rest-client to 7.0.0

Change-Id: Ia39f27f261bf28d1e70cdcd984d8e1f57e03f30e
tree: a3ca14771544e3adcb99173ed218e44e3be7165f
  1. java/
  2. javatests/