On Mon, 17 Apr 2023 13:08:41 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> Yes, it is implementation-specific, that is why it says "Hotspot's identity >> hash code". The relevant code blocks are >> https://github.com/openjdk/jdk/blob/cc60f2ff3f16bdb04917e09cb87f09bd544f1f8b/src/hotspot/share/oops/markWord.hpp#L231-L233 >> (property) and >> https://github.com/openjdk/jdk/blob/cc60f2ff3f16bdb04917e09cb87f09bd544f1f8b/src/hotspot/share/runtime/synchronizer.cpp#L826-L827 >> (invariant). > > It would not break the code functionally if that invariant ever breaks: we > would "just" call the (intrinsic) method on zero hash code. That `implNote` > only shows that it would not happen with current implementation at all. >From that impl note it seemed like it was a big deal for hash code to never >return 0 for an object. Could you maybe de-emphasize the importance of that >HotSpot behavior in the note? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13491#discussion_r1168725310
