Re: [jetty-discuss] Embedded Jetty having shutdown hook problems

[Chris H. <ch...@ha...>]

I think your problem is that Jetty kills all its Listener threads
during shutdown, and you are using one of those threads to do that
shutdown - you are instructing it to commit suicide.

You need to activate the shutdown using a thread that is not a child
of one of Jetty's ThreadPools.

I would try something like this....:


public class MortalServer extends org.mortbay.http.Server{

private static String assassinFlag = "";

private Runnable assassin = new Runnable(){
            public void run(){
                    synchronized(assassinFlag){
                            assassinFlag.wait();
                            System.exit();
                    }
            }};

public void start(){
            Thread t = new Thread( assassin  );
            t.setDaemon(true);
            t.start();

            super.start();            /// Normal Jetty Server start
}//--------------

public static void kill(){
        synchronized(assassinFlag ){  assassinFlag.notifyAll();   }
}//--------------

}//================


Now start Jetty with
    new MortalServer().start();

and to make the whole JVM stop  call
    MortalServer.kill();  which can be called from within a Jetty
webApp using a Jetty Listener thread.


HTH

Chris

----- Original Message -----
From: "Greg Billock" <gbi...@is...>
To: <jet...@li...>
Sent: Tuesday, October 21, 2003 10:24 PM
Subject: [jetty-discuss] Embedded Jetty having shutdown hook problems


> Thanks all for a fantastic embedded JSP/servlet engine. Jetty
> is a real treat to work with.
>
> The application I'm working on uses a Runtime shutdown hook to
> shut down various embedded modules, one of which is a module
> which wraps a Jetty server, which we run embedded. It is working
> very well, with the following hiccup:
>
> When I run the application stand-alone, i.e. from the command
> line, and hit Ctrl-C to shut it down, everything works fine --
> my shutdown hook activates and calls the shutdown lifecycle
> method on all my modules, including Jetty (which invokes
Server.stop).
>
> The puzzle is when I invoke System.exit from a thread launched
> by Jetty as part of a web application. The JDK docs say that this
> will initialize the shutdown hook, which it does, but my shutdown
> thread seems to terminate somewhere in the Server.stop method
> when I use this mechanism.
>
> As a workaround, I tried another method where I unregister my
> shutdown hook and run a new thread which does the same job, and
> then just wait for all the non-daemon threads to terminate. Oddly
> enough, the same thing happens: my modules shut down until it
> gets to the Jetty module, at which point the thread dies. This
> is true whether we call Server.stop or Server.stop(graceful=true).
>
> I've checked and the thread isn't a daemon thread, and I've
> looked through the Jetty code trying to find a smoking gun there,
> but found nothing suspicious. I suspect an odd interplay with
> a JVM irregularity and something Jetty is doing subsequent to
> Server.stop which exercises that irregularity. Any ideas?
>
> The workaround we're using for now: don't call Server.stop and
> allow the daemon threads inside Jetty to terminate abruptly.
> This seems to work out OK for us, but I'm not sure it is a good
> answer, especially if we were to depend on other Jetty-provided
> resource management or anything.
>
> -Greg Billock
>
>
>
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