I have a init.d script which starts/stops a jruby based server running on java 8. It first does it the nice way with a kill and then after a while it falls back to a kill -9. I can see from my logs that the kill triggers the right shutdown hooks and eventually it calls System.exit(0). At this point the process should die, except it doesn't.
I've actually polled with a loop inside my init.d script whether the process still exists at that point (yes) and tried with a kill -QUIT to make it log a thread dump. The latter stops working after a few seconds but the process zombies along until I kill -9 it.
My question: how can I determine what is causing this? At least a thread dump would tell me what part of my code is blocking but it seems to be in a state where that no longer works and yet the process does not exit.
The suggestion by Joe to use Runtime.getRuntime().halt(int) works. Thanks