Summary:
In the `.travis.yml` file the `jdk: openjdk7` element is ignored when `language: cpp`. So whatever version of the JDK that was installed in the Travis container was used - typically JDK 11.
To ensure our RocksJava builds are working, we now instead install and use OpenJDK 8. Ideally we would use OpenJDK 7, as RocksJava supports Java 7, but many of the newer Travis containers don't support Java 7, so Java 8 is the next best thing.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6512
Differential Revision: D20388296
Pulled By: pdillinger
fbshipit-source-id: 8bbe6b59b70cfab7fe81ff63867d907fefdd2df1