On Thu, 29 Jan 2026 09:12:21 GMT, Alan Bateman <[email protected]> wrote:
>> src/hotspot/share/services/threadService.cpp line 1479:
>>
>>> 1477: if (cl._thread_status == JavaThreadStatus::NEW || cl._thread_status
>>> == JavaThreadStatus::TERMINATED) {
>>> 1478: return nullptr;
>>> 1479: }
>>
>> It is not obvious to me why this is only a possibility now?
>
> ThreadSnapshot.of(Thread) may be invoked with a platform or virtual Thread in
> any state. It could sample the thread state before calling
> ThreadSnapshotFactory::get_thread_snapshot. That would allow it to filter out
> unstarted/NEW threads. It could also filter terminated threads but that would
> be racy and get_thread_snapshot would still need to handle terminated threads.
>
> For platform threads, get_thread_snapshot will bail out early if there is no
> JavaThread. So the effect of the above is to have virtual threads also be
> filtered out.
Still not clear to me why any new thread is not already filtered out long
before now; nor why we have not needed this in the past.
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PR Review Comment: https://git.openjdk.org/jdk/pull/29461#discussion_r2744583241
