Hi,

A little ... more elegant & less performance consuming solution was to change writeLoop() and return 'false' when waitOnMonitor returns one (receiving an interrupt):

boolean writeLoop()
        {
        Job job = null;
        
        try
            {
            synchronized(jobs)
                {
                // check for an unsent job
                if ((job = oldestUnsentJob()) == null)  // automatically marks as sent
                    {
                    // failed -- wait and drop out of the loop and come in again
                    debug("" + Thread.currentThread().getName() + "Waiting for a job to send" );
                    if (!slaveMonitor.waitOnMonitor(jobs))							// changed
                    	return false;										// new
                    }
    ...

Avoiding a busy waiting ... writer.isInterrupted ... of the previous version.

	Ralf

On Sep 6, 2013, at 14:41, Ralf Buschermöhle <[log in to unmask]> wrote:

> 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>
>> 
>> 
>