Hi,

unfortunately adding memory does not solve the problem. 

It does not seem to be heap related ... I jstacked after 56 slaves, after 500 adding and removing (also waited for the disconnect messages) slaves and after the next 500 I received the Exception.

And the number of threads did not reduce after waiting.

I attached the thread dumps.

It's the slaveMonitor ... who does not receive an interrupt?

 public boolean waitOnMonitor(Object monitor)
        {
        try
            {
            monitor.wait();
            }
        catch (InterruptedException e) { return false; }
        return true;
        }

Greetings,

	Ralf