Thanks a lot for helping.
More problems:

In eclipse, Preview of features is supported only at the latest source level
JAVA_RELEASE isset to 24
Executing eclipse compiler on generated resources with all warnings suppressed...
Content of target/eclipse/report.txt:
Preview of features is supported only at the latest source level
[ERROR] Command execution failed.

Thanks a lot for help.

Please apply https://github.com/checkstyle/checkstyle/wiki/How-to-run-certain-phases-and-validations#how-to-create-commit-that-skips-all-ci
To let you run only semaphore, and not other CIs

Thanks for pointing that out, sorry for not isolating just semaphore CI test.

@romani

Thank you so much for being patient with me while I was burning CI credits.
I'm happy to say, the error has been resolved.

do I need to re run in order to pass the Internal Server Error (500) error: Pitest / test (api) (pull_request)? can you please re run it so it passes?

Solution

As of now, I've pinned the version of Eclipse to R-4.37-202509050730 rather than have it scrape the newest version. I've made this change because I believe we need to be ready before transitioning to their updates to not break our CI pipelines. I hope that makes sense.

This is not a fix for issue to use latest eclipse static analysis, but it is workaround to stop using latest from web and use what is already in our artifacts cache.

Please put in commit message reference to this PR , "Pull #18253: ....". We will merge this PR as workaround, and we will change issue to be for migration to new eclipse version

Thanks for replying, I'll make all the changes as requested. I must have missed them.

Though I'm curious about the long-term strategy here, I want to understand properly. If we revert to a dynamic version in the future, doesn't that leave the CI pipeline vulnerable to breaking again whenever a new update is released? (sort of like this instance?)

Or is the goal to intentionally break early so we can ensure CheckStyle always adheres to the latest static analysis standards, rather than accumulating onto an older version?

vulnerable to breaking again whenever a new update is released?

It was was that fragile.
On stable version it becomes hard to remember to update, so we will stay in old for years until someone notices this.