Over the last few hours I activated findbugs on the Dataflow Java worker and fixed or suppressed the errors. They started around 60 but fixing some uncovered others, etc. You can see the result at https://github.com/apache/beam/pull/7684.
It has convinced me that findbugs still adds value, beyond errorprone and nullaway/checker/infer. Quite a few of the issues were not nullability related, though nullability remains the most obvious low-hanging fruit where a different tool would do even better than findbugs. I have not yet enable "non null by default" which exposes 100+ new bugs in the worker, at minimum. Are there known blockers for upgrading to spotbugs so we are depending on an active project? Kenn
