Thousands of threads spawned from Java process... why?

I have a problem with a recent customer migration to Linux (64-bit) when running a Java process.

The process is spawning thousands of threads most with an identifier of futex. I've looked up futex (fast userspace mutex) and it's a Linux construct to implement basic locking.

The code has recently changed to implement a BlockingQueue and an ExecutorService to spawn child threads but the number of child threads is controlled by a config setting and I can prove that this specific mechanism is not running out of control. I can only assume that something internal to the JVM is spawning all these threads due to the BlockingQueue and some lock?

So can anyone tell me 开发者_Python百科how to find out what these threads actually are and what I might do to control/stop them?

Below is a few lines of the process list; the actual list before the process had to be killed was over 13000 lines long.

0 - 54321 447 446 1 - - - 5953085 - ? 00:15:50 java

0 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

1 S 54321 - - 0 82 2 - - futex_ - 00:00:00 -

Any suggestions gratefully accepted.

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If you cannot load the application in the debugger of an IDE, you might want to load the application with VisualVM to look at what the threads are actually doing:

http://download.oracle.com/javase/6/docs/technotes/guides/visualvm/threads.html

Make sure you can kill the app, as it might run out of resources because of the high number of threads (i.e. in linux, have a shell ready).