Jason Tedor 0a79555a12 Require JDK 9 for compilation (#28071) ... This commit modifies the build to require JDK 9 for compilation. Henceforth, we will compile with a JDK 9 compiler targeting JDK 8 as the class file format. Optionally, RUNTIME_JAVA_HOME can be set as the runtime JDK used for running tests. To enable this change, we separate the meaning of the compiler Java home versus the runtime Java home. If the runtime Java home is not set (via RUNTIME_JAVA_HOME) then we fallback to using JAVA_HOME as the runtime Java home. This enables: - developers only have to set one Java home (JAVA_HOME) - developers can set an optional Java home (RUNTIME_JAVA_HOME) to test on the minimum supported runtime - we can test compiling with JDK 9 running on JDK 8 and compiling with JDK 9 running on JDK 9 in CI		2018-01-16 13:45:13 -05:00
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build.gradle	Require JDK 9 for compilation (#28071)	2018-01-16 13:45:13 -05:00