Re: java.lang.IllegalStateException: Deadlock risk: AWT tree lock acquired on a showing component..

Eric Sosman <>
Thu, 24 May 2007 17:55:12 -0400
Tom Hawtin wrote On 05/24/07 17:27,:

Eric Sosman wrote:

Cherukan wrote On 05/24/07 14:45,:

As the message says, I cant use invokeAndWait.

Whats the 'safe' approach in such a case?

   (Warning: not tested.) The long-running worker
thread uses invokeLater() to cause the EDT to display
the dialog, and then puts itself to sleep by calling
wait() on some convenient object. When the dialog
gets the desired response, it puts the input into the
aforementioned convenient object and calls notify()
to awaken the sleeping worker thread.

That's effectively what invokeAndWait does. Rolling your own version
wont help.

    You could be right, but I'd be surprised if my
suggestion would risk deadlock. (Perhaps I should
have said that by "some convenient object" it was to
be understood that the object wasn't a GUIgadget,
but a plain old StringBuilder or ArrayList or some
such "free-standing" sort of object.)

    I'll be the first to admit that I find the code
for EventQueue.invokeAndWait() to be impenetrable.
For example, the call to lock.wait() looks like an
obvious beginner bug (Where's the state test? What
about spurious wakeups?) -- but if it were a bug it
would surely have surfaced by now, so there must be
a good deal more going on than meets my eye.


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