我可以在Junit测试中检测到泄漏的线程吗？

Question

I've got some code that forgets to set the daemon flag on a thread. Thus, main methods don't ever complete. I'll track it down eventually, but I wonder: is there any way to reflectively notice the existence of non-daemon threads so that a JUnit (or testng, or whatever) test could complain in this case? Note that these test frameworks orchestrate System.exit so that the excess threads don't manifest as hangs.

Answer 1

You can get a list of all running threads ( Get a List of all Threads currently running in Java ):

Set<Thread> threadSet = Thread.getAllStackTraces().keySet();

Then you can iterate through the list in some test that you write calling Thread.isDaemon() . You'll probably need to throw out some threads that correspond to the JVM or the JUnit framework, but that's probably doable by checking other aspects of the threads, like their name.