Experiencing an issue with ScheduledExecutorService alongside VT

[Alan Bateman]

On 21/07/2024 18:10, Yuval Lombard wrote:
> Hi Robert
>
> Thanks for your reply and feedback.
> Unfortunately I have no choice but using the MQTT 3rd party lib
>
> Attaching also the jcmd thread dump as you suggested.
> Hope it would be helpful

There are 120k virtual threads. Most of them have empty stack traces  so 
I assume they have been started but haven't executed yet. The dump is 
hinting that it is something timer related. There are two virtual 
threads (#1561853 and #1561856) doing Socket.connect with a timeout and 
both are scheduling to be unparked if their connection isn't established 
before the timeout expires. At the same time, some other virtual thread 
(not sure which) has just unmounted from ForkJoinPool-1-worker-4 due to 
contention trying to enter a monitor. ForkJoinPool-1-worker-4 is attempt 
to schedule the virtual thread to unblocked after a short delay. So I 
think you are running into a bug but I think we need to see if 
duplicates with the more recent EA build.

-Alan