Re: Applets and ThreadGroups (Was: Re: ThreadDeath - How spooky is that!)

From:
"Richard Maher" <maher_rj@hotspamnotmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 30 Jul 2009 22:35:50 +0800
Message-ID:
<h4savk$l2q$1@news-01.bur.connect.com.au>
Hi Mark,

"markspace" <nospam@nowhere.com> wrote in message
news:h4qmen$8o1$1@news.eternal-september.org...

Richard Maher wrote:

What version of Browser, OS, and JVM were you using?


Firefox 3, Vista, Java 1.6 something (the latest).

If it's Java 6, did you have the "classloader_cache" applet parameter

set to

true?


Yes. Which is to say I left it at its default value.

<https://jdk6.dev.java.net/plugin2/#CLASSLOADER_CACHE>

Can you please post your Applet code so that I can try here?


It's pretty simple. This code will print "test = 0" when it is loaded
fresh and "test = 1" when it is used from the applet cache:

<CODE>
package testapplet;
import javax.swing.JApplet;

public class TestApplet extends JApplet {

     static int test;

     @Override
     public void init() {
         System.out.println( "Init" );
         System.out.println( "static int test = " + test );
         test = 1;
     }

     @Override
     public void start() {
         System.out.println( "Start" );
         new Thread() {
             @Override
             public void run() {
                 System.out.println( this );
                 try {
                     for(;;);
                 } catch (Error er ) {
                     System.err.println( er );
                 }
             }
         }.start();
     }

     @Override
     public void stop() {
         System.out.println( "Stop" );
     }

     @Override
     public void destroy() {
         System.out.println( "Destroy" );
     }

}
</CODE>

Here's the applet tag I used in the web page:
<html>
     <head>
         <meta http-equiv="Content-Type" content="text/html;

charset=UTF-8">

         <title>JSP Page</title>
     </head>
     <body>
         <h1>Hello World!</h1>
         <applet code="testapplet.TestApplet"
             archive="AppletOne.jar"/>
     </body>
</html>


Thanks very much for the example!

but if
he's right then you've managed to unload the JVM system class loader

while

the browser is still running. How did you do that? Or are you not using

the

System Class Loader?


Nope, I just waited for the JVM itself to stop. The plug-in does that
once it is no longer used.


Mine doesn't seem to. This is perplexing (for me anyway) Looks like you're
writing to the Java console; does the console window too just disappear
after 30 secs? Was was the console output before it disappeared?

You are running an Applet in a Browser aren't you?


Correct.


Just had something go live so I'm knackered and will jump into bed but
didn't want you to think I was dodging the post or ungrateful.

Thanks again. I'll look more on tomorrow or w/e.

Regards Richard Maher

PS. File URL/codebase have anything to do with it? Some other settings I've
got that you ain't? I'm seeing things again :-)

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