From which thread should System.exit() be called in a Swing-app?

Question

In a Swing-app is it okay to invoke System.exit() from any thread? (e.g. on the EDT?)

Answer 1

It is safe to call System.exit from any thread but not from the shutdown hook thread. I recently had to debug such flow https://knotgillcup.blogspot.com/2019/08/systemexit-not-working.html

Even more brutal way to terminate JVM is to call Runtime.halt() method.