Can I use thread.stop () in Java if I really need it?

Question

I need to use deprecated stop () because I need to run Runnable classes which were developed by other programmers and I can't use while (isRunning == true) inside method run.

The question is: Is it safety enough to use method stop ()? Theads don't work with any resources (like files, DB, or Internet connections). But I want to be sure that JVM wouln't be corrupted after I stop a dozen of threads with stop () method.

P.S.: yes, I can write some code to test it, but I hope somebody knows the answer)

Answer 1

Sort of. There's nothing inherently "corrupting" about Thread.stop(). The problem is that it can leave objects in a damaged state, when the thread executing them suddenly stops. If the rest of your program has no visibility to those objects, then it's alright. On the other hand, if some of those objects are visible to the rest of the program, you might run into problems that are hard to diagnose.

Answer 2

The JVM won't be corrupt, but read the javadocs closely to make sure that you don't meet their conditions for "disaster."

You'll need to take a close look at any synchronization monitors that the thread is holding onto. You mentioned files and sockets as resources being hung onto, but you'll also need to consider any shared data structures. Also make sure your exception handling doesn't catch RuntimeExceptions (see stop()).

Answer 3

If you use Thread.stop you'll probably get away with, assuming you have few users. It is exceptionally hard to test for. It can cause an exception anywhere in executing code. You can't test all possible situations. On your machine in your set up you might never find a problem; come the next JRE update your program might start failing with a highly obscure intermittent bug.

An example problem case is if the thread is loading a class at the time. The class fails to load and will not be retried again. You program is broken.

Answer 4

I addressed this in my question "Are thread stop and friends ever safe?", and in one of the answers, I tried to figure out preconditions that would make stop() safe to use. But this is still a "work in progress".

BTW: writing test code won't necessarily help. (Tests only prove the presence of bugs not the absence of bugs.) You would do better trying to reason about the problem, IMO. But it is not easy :-).