WAITING at sun.misc.Unsafe.park(Native Method)

Question

One of my applications hangs under some period of running under load, does anyone know what could cause such output in jstack:

\"scheduler-5\" prio=10 tid=0x         


        

Answer 1

From the stack trace it's clear that, the ThreadPoolExecutor > Worker thread started and it's waiting for the task to be available on the BlockingQueue(DelayedWorkQueue) to pick the task and execute.So this thread will be in WAIT status only as long as get a SIGNAL from the publisher thread.