I just added the option in main

There is no option but it’s very easy to add. Try it! I agree that JDT is a different case to IntelliJ and Gradle/Maven, and might not benefit from the index.

@Christian Beikov is there already an option to disable the index write, that i could try? JDT should have most things in memory (and even much more then the current project which makes it need to slowly search what is reachable) while on windows writing an index to disk also calls the indexer, virus scanner and so on which can slow down things even more.

It would be interesting to just try disabling writing the index, to see whether it really helps. The reason it was added is that @Christian Beikov argued that scanning all modules for an entity was going to be unacceptably slow (which is plausible). But we don’t know for sure that this is true in Eclipse, and I guess it’s perfectly possible that writing to disk is slower than scanning stuff that the IDE probably already has cached in memory. You would need to try it out.

What i did:

1. removed hibernate-validator from factorypath to disable 2nd annotation processor

2. updated factorypath to hibernate-jpamodelgen-6.6.4-SNAPSHOT.jar, hibernate-core-6.6.4-SNAPSHOT.jar

The result is ~20sec annotation processing:

Open

I again ran the scenario with 6.6.2 also with removed hibernate-validator, to see the effect of the changes in jpamodelgen only:

Open

One can see that you successfully reduced the hotspot in processClasses() so that now mainly the writeIndex() hotspot remains, which was already present in 6.6.2 but not in 5.6.15.

Thank you very much for your effort and stunning respond time. If you could also improve the writeIndex() (or can that index be disabled?) i would be happy to test that too.