From the documentation for Elasticsearch 2.3:
Elasticsearch requires at least Java 7. Specifically as of this writing, it is recommended that you use the Oracle JDK version 1.8.0_73.
I notice that the documentation doesn’t recommend at least version 1.8.0_73; it recommends that specific version. Is that deliberate? Or should we feel free to use the latest Oracle JDK 8 release?