There was a microsoft prototype for more stack allocation in OpenJDK (https://archive.fosdem.org/2020/schedule/event/reducing_gc_t...). I recall that being put on hold because of how it would interact with project Loom fast stack copying. But I don't know the current status.

GO has a non moving GC and I understand, that the cost of introducing safe moving GC is considered high. If one has a moving GC which the serious java one's are read/write barriers are already required, especially if they are concurrent like ZGC, C4 or Shenadoah. ZGc, C4 and Shenadoah all started out as non generational GC implementations, which gained them later, because in most cases they do increase performance/reduce overhead.

Valhalla makes objects denser, and reduces overhead of identity which is great. Reducing the difference in memory layout between java objects and nested go structs.

Go with arena's reduce the GC de-allocation costs. Something that the ZGC team is looking at in relation to loom/virtual threads. (but I can't find the reference for that right now)