RFR: 8365823: Revert storing abstract and interface Klasses to non-class metaspace [v3]

Wed Sep 17 17:36:56 UTC 2025

On Mon, 15 Sep 2025 14:38:03 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This change removes the optimization to not store abstract and interface Klass metadata to non-class metaspace.  Now all Klass metadata is in the Klass metaspace.  This is simpler and less bug prone, and didn't help with the limitation of classes that can be stored in class metaspace materially.
>> Tested with tier1-4.
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove CFP.is_abstract().

Yes, this wasn't just a backout.  I stayed away from the JFR code refactoring, and there were other fixes for hidden classes that are already in JDK 25. And we added then backported a diagnostic flag, that this change removes.

Yes, this change should backport cleanly to JDK 25 pending approval.
Thanks for reviewing Aleksey and Vladimir.

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PR Comment: https://git.openjdk.org/jdk/pull/27295#issuecomment-3303955655
PR Comment: https://git.openjdk.org/jdk/pull/27295#issuecomment-3303957791