Hardcoded test for JDK 8, 11, or 16 is problematic

[eikemeier]

When running in JDK 17 LTS, the annotation processor checks for JDK 8, 11, or 16 and emits a warning when running on another platform:

https://github.com/typetools/checker-framework/blob/checker-framework-3.18.1/framework/src/main/java/org/checkerframework/framework/source/SourceChecker.java#L537

This warning is not easily suppressed and terminates a build running with -Werror. While the intention is good, it would be preferable to be able to build on JDK 17 without workarounds.

The plugin should either just emit a Kind.NOTE or prove a flag to suppress this warning. I'm willing to submit a patch for either solution.

[mernst]

You are right. Thank you for pointing out that we overlooked updating this when JDK 17 was released, and my apologies for the inconvenience.

With 42255c9 (plus commits in a number of related repositories), the Checker Framework supports, and is tested under, JDK 17. It probably works on all versions 8+, though in the past, it would crash when run on the wrong version, which was the reason for the hard error. We should remove that in the future, though we don't want to commit resources to versions of Java that are no longer supported.

Thanks again, and please let us know if you have any other problems.

[eikemeier]

Thanks, looks great. How about not removing it in the future, but using Kind.NOTE now?

[mernst]

OK, I have done so in #4943. Thanks for the nudge.