EJBCLIENT-241 Shut down executor service in EJBClientContext

[TomasHofman]

https://issues.jboss.org/browse/JBEAP-8577
https://issues.jboss.org/browse/EJBCLIENT-241

[elguardian]

Aren't you getting rejection execution exception with this change ?

[TomasHofman]

So far I didn't notice, I'll do some more experiments. Are you getting those or just suspecting?

[elguardian]

I just suspect that could happen... but very edge cases. You should ask David. I remember that the shutdown was there at some point but cannot remember when.

[TomasHofman]

I checked the code once more - tasks are submitted to ejbClientContextTasksExecutorService in methods:

• registerEJBReceiver()
• unregisterEJBReceiver()
• attemptReconnections()

Intuitively I think none of these methods should be called on closed context, apart perhaps from unregisterEJBReceiver(). All ejb receivers are however unregistered in the close() method, so there's no reason to do that again (but who knows).

https://github.com/jbossas/jboss-eap7/blob/7.0.x/ejb3/src/main/java/org/jboss/as/ejb3/remote/DescriptorBasedEJBClientContextService.java#L117 - here it calls unregister and close in correct orther.

[elguardian]

attemptReconnections can be executed at any time... that is the reason you have a close check in the ReconnectHandler... The offending commit about not shuting down is this one:

87aef56

@bmaxwell can give away more info about why he removed that line

[TomasHofman]

Hmm, that looks quite relevant.

[elguardian]

I think you can bypass the problem related to execute tasks avoiding the rejected execution exception. The trick would be to use the RejectedExecutionHandler somethink like this....

ThreadPoolExecutor service = (ThreadPoolExecutor) Executors.newCachedThreadPool(new DaemonThreadFactory("ejb-client-context-tasks"));
service.setRejectedExecutionHandler(new RejectedExecutionHandler() {

	@Override
	public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
		if(executor.isShutdown()) {
			System.out.println("this in theory should not happen");
		}
		r.run();
	}
			
});

so even if you shutdown the executor you will execute the task in the caller thread... You can add some stacktrace if you are calling the executor after closing the context.

[TomasHofman]

The thing is I didn't manage to reproduce RejectedExecutionHandler at all. It may've been a problem in earlier version which is now fixed.

[TomasHofman]

Closing this for now until the other necessary fixes are figured out.