We package a specific revision of javac and use it for Error Prone. Currently this is a ~year old version of javac 9, which means that: 1) You have to execute

We package a specific revision of javac and use it for Error Prone. Currently this is a ~year old version of javac 9, which means that: 1) You have to execute your compiler on JDK >=8. 2) You cannot target bytecode <= Java 5.