Hi, I added "!writer.isInterrupted()" to stop the (write)loop and now the threads are stopped. In context "SlaveConnection.java" writer = new Thread() { public void run() { while( !writer.isInterrupted() ) writeLoop(); } }; Greetings, Ralf On Sep 6, 2013, at 11:59, Ralf Buschermöhle <[log in to unmask]> wrote: > 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 > > > <56.stack><56+-500.stack><Exception.stack> > >