Threading in an Application Server

Question

I have a Java program/thread that I want to deploy into an Application Server (GlassFish). The thread should run as a "service" that starts when the Application Server starts and stops when the Application Server closes.

How would I go about doing this? It's not really a Session Bean or MDB. It's just a thread.

Answer 1

I've only done this with Tomcat, but it should work in Glassfish.

Create a Listener class that implements javax.servlet.ServletContextListener, then put it in web.xml. It will be notified when your web app is started and destroyed.

A simple Listener class:

public class Listener implements javax.servlet.ServletContextListener {

    MyThread myThread;

    public void contextInitialized(ServletContextEvent sce) {
        myThread = new MyThread();
        myThread.start();
    }

    public void contextDestroyed(ServletContextEvent sce) {
        if (myThread != null) {
            myThread.setStop(true);
            myThread.interrupt();
        }
    }

}

This goes in web.xml after your last 'context-param' and before your first 'servlet':

<listener>
    <listener-class>atis.Listener</listener-class>
</listener>

Don't know whether this kind of thing is recommended or not, but it has worked fine for me in the past.

Answer 2

This is not something that you should do in any app server, unless you have access to managed threads provided by the app server. I am not familiar with Glassfish, but you could do this in Websphere or Weblogic using a commonj WorkManager.

Apparently, the same can be accomplished in Glassfish and JBOSS via a JCA WorkManager (which I am not familiar with).