Is it possible view/pause/kill a particular thread from a different java program running on the same JVM

In this tutorial we are going to understand about the possibilities of view/pause/kill a particular thread from a different java program running on the same JVM.

The java debugger will allow you to kill a thread by injecting an exception into it. I was just trying to work out how to use this feature to kill a thread without wiping out the whole jvm, when I came across this question. If you run the jvm with command line options like:

java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8888 your.app.Main

and connect the debugger with something like:

jdb -attach 127.0.0.1:8888

you can type:

threads

To get a list of the running threads, and use the kill command to kill a running thread. The bit I’m currently not sure about is the syntax of this kill command, I have tried the obvious:

kill 0xe2e new java.lang.IllegalArgumentException("er");

and I get the messages:

killing thread: Swank REPL Thread
Thread not suspended
Expression must evaluate to an object

You could do this even without a separate application. Write your own startup class, which performs a pass-through of parameters to the original startup class of the application. Your class’s main method though would create a thread that periodically checks the list of all threads (e.g., Thread.getAllStackTraces or Thread.enumerate), finds the offending thread, and invokes stop() on it. Although Thread.stop is deprecated, it still works.

Another option is to run the application under a Java debugger, say, jdb and then suspend/kill the required thread. You could also add parameters to the application’s startup so that the JVM can be attached to, then attach jdb to the running JVM and suspect/kill the thread.