[Question] How to enable annotation processing

[mbauhardt]

background
I want to emacs-lsp/lsp-java to compile/build a gradle based java project which uses annotation processing to generate source code.
I found https://github.com/emacs-lsp/lsp-java/blob/master/lsp-java.el#L1768 which let me hope that this feature is possible.

Steps to reproduce
So I updated my doom emacs lsp-java config to revision e78199d
and tried to build a small demo project https://github.com/mbauhardt/ecj-filer-exception without success
Because I'm new into emacs I'm pretty sure I do something wrong.

Final Question
Can someone help me and give me some hints how to enable my emacs config to support annotation processing to generate code?

thx.
marko