Stop scheduled timer when shutdown tomcat [duplicate]

Answer 1

Try to use framework for scheduling.

If you adapt Spring Framework you could use the build in scheduling capabilities.

When scheduling with Spring I had never any problem stopping application server.

Answer 2

The servlets destroy method is called as the servlet is about to be unloaded. You could cancel the timer from within there, providing that you altered the scope of the parserTimer itself to make it an instance variable. I don't see a problem with that provided that you access it only from within init and destroy.

The servlet engine is free to unload the servlet whenever it sees fit, but in pratice I'm only ever seen it called as the servlet engine is stopped - other people may have other experiences of this though that might prove me wrong.

Answer 3

Do not use Timer in an Java EE environment! If the task throws a runtime exception, then the whole Timer is killed and won't run anymore. You basically needs to restart the whole server to get it to run again. Also, it is sensitive to changes in the system clock.

Use ScheduledExecutorService instead. It's not sensitive to exceptions thrown in tasks nor to changes in system clock. You can shutdown it by its shutdownNow() method.

Here's an example of how the entire ServletContextListener implementation can look like (note: no registration in web.xml required thanks to the new @WebListener annotation):

@WebListener
public class BackgroundJobManager implements ServletContextListener {

    private ScheduledExecutorService scheduler;

    @Override
    public void contextInitialized(ServletContextEvent event) {
        scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.scheduleAtFixedRate(new YourParsingJob(), 0, 5, TimeUnit.HOUR);
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        scheduler.shutdownNow();
    }

}

Answer 4

Put parseTimer.purge() in your onContetexyDestroyed.It will remove all the timers in the queue if they exist.