Spring webapp

Question

I am instantiating a ScheduledExecutorService using Spring's ApplicationListener interface as follows:

@Component
public class ExecutorsStart implements ApplicationListener<ContextRefreshedEvent> {

    private ScheduledExecutorService executor;

@Autowired
Scheduler scheduler;

@Override
public void onApplicationEvent(final ContextRefreshedEvent event) {
    executor = Executors.newSingleThreadScheduledExecutor();
    scheduler.init();
    int delay = 10;
    int period = 60;// repeat every 1 minutes.
    executor.scheduleAtFixedRate(scheduler, delay, period, TimeUnit.SECONDS);
}

At the moment, Tomcat won't shut down cleanly when I run, ./shutdown.sh, with message:

The web application [/foo] appears to have started a thread named [pool-1-thread-1] but has failed to stop it

and this seems to be because I have not yet written code to stop the ScheduledExecutorService.

My question is: how should this be done properly in this environment?

I noticed that there exists a ContextStoppedEvent, so, I implemented a listener for it:

@Component
public class ExecutorsStop implements ApplicationListener<ContextStoppedEvent> {

@Autowired
ExecutorsStart executorsStart;

@Override
public void onApplicationEvent(final ContextStoppedEvent event) {
    executorsStart.executor.shutdownNow();
}

But it seems that this event handler doesn't get called when Tomcat is shutdown.

Have I implemented this incorrectly, or am I going about this completely the wong way?

Sotirios Delimanolis · Accepted Answer · 2014-03-26 02:55:56Z

You're looking for ContextClosedEvent.

@Component
public class ExecutorsStop implements ApplicationListener<ContextClosedEvent> {

    @Autowired
    ExecutorsStart executorsStart;

    @Override
    public void onApplicationEvent(final ContextClosedEvent event) {
        System.out.println("Stopped: " + event);
    }
}

When the Servlet container shuts down, it calls contextDestroyed(..) on its various ServletContextListener and destroy() on its Servlet instances. The ContextLoaderListener and DispatcherServlet each call close() on their ApplicationContext.

Is the PreDestroy annotation you mention in stackoverflow.com/a/22544982/55070 not enough for doing so?– leo Aug 27 '14 at 12:13 — leo, Aug 27 '14 at 12:13
@lep Sure, preDestroy could work here too. – Sotirios Delimanolis Aug 27 '14 at 14:24 — Sotirios Delimanolis, Aug 27 '14 at 14:24

Spring webapp

1 Answer