* Make Errorprone the default compiler
* Address comments
* Make Error Prone's ClassCanBeStatic rule a error
* Preconditions allow only %s pattern
* Fix DruidCoordinatorBalancerTester
* Try to give the compiler more memory
* Remove distribution module activation on jdk 1.8 because only jdk 1.8 is used now
* Don't show compiler warnings
* Try different travis script
* Fix travis.yml
* Make Error Prone optional again
* For error-prone compiler
* Increase compiler's maxmem
* Don't run Error Prone for benchmarks because of OOM
* Skip install step in Travis
* Remove MetricHolder.writeToChannel()
* In travis.yml, check compilation before tests, because it may fail faster
* Fix#3795 (Java 7 compatibility).
Also introduce Animal Sniffer checks during build, which would
have caught the original problems.
* Add Animal Sniffer on caffeine-cache for JDK8.