Move Recycler to log4j-kit

[ppkarwasz]

This PR depends on #2396.

We move Recycler interface introduced in #1969 from log4j-api to log4j-kit.

Since the only current user of Recycler is Log4j Core 3.x, we removed the static recycler registry and replaced it with an entry in DefaultBundle.

This also closes #2106.

[vy]

I completely agree that recycler concept should not be part of the -api, but -kit. Hence, great initiative! 💯

I don't see any blockers, though dropped some minor remarks/questions.

I have the impression that certain file move+edit ops could not get tracked by Git properly and hence appear as new files. This makes reviewing difficult. I don't know if there is much you can do about it. But wanted to share it anyway.

[vy]

Shouldn't this class be located in a log4j-kit-test artifact instead? I know, this implies moving log4j-kit/src/test to log4j-kit-test/src/test, but be it, just like log4j-core-test and log4j-api-test.

Could you also add some Javadoc, please?

[vy]

Since the only current user of Recycler is Log4j Core 3.x, we removed the static recycler registry and replaced it with an entry in DefaultBundle.

This is not correct. There are other modules besides log4j-core that use recyclers, for instance JTL.

[ppkarwasz]

Since the only current user of Recycler is Log4j Core 3.x, we removed the static recycler registry and replaced it with an entry in DefaultBundle.

This is not correct. There are other modules besides log4j-core that use recyclers, for instance JTL.

What I meant is that only Log4j Core and its sub-modules use recyclers explicitly. Implementations such as log4j-to-jul and log4j-to-slf4j are based purely on log4j-api, so they will loose Recycler support after Log4j API 3.x is removed.