I'm not certain that it's a good idea to use jspecify mode yet, I think that's pretty significantly under development. YMMV, but jspecify mode isn't needed just because you're using those annotations. On the other hand, if it works... was looking at this PR for a different reason anyways.

Thank you for pointing that out!
I'm aware that the logic under this flag is still under development.
For me, enabling JSpecifyMode is a way to contribute to the community, any unexpected behavior we encounter in NullAway can be reported to its creators to help improve the tool.
Since this is a build-time tool, it's safe for the semver4j project - if critical issues occur with the tool, we can simply remove the -XepOpt:NullAway:JSpecifyMode=true flag.

@piotrooo WDYT?

For me, it's ok. I saw a couple of projects that moved to JSpecify. I think it's a good move.