JMS in Applets

[umar]

I have a problem in an applet client of jbossmq. This is the same bug as in
http://jboss.org/index.html?module=bb&op=viewtopic&t=40438

The Connection class uses a static ThreadGroup which gets destroyed
by the Browser on reload, and the code is not capable to reinitialise it.

java.lang.NoClassDefFoundError
 at org.jboss.mq.SpyJMSException.<init>(SpyJMSException.java:79)
 at org.jboss.mq.Connection.authenticate(Connection.java:1168)
 at org.jboss.mq.Connection.<init>(Connection.java:255)
 at org.jboss.mq.Connection.<init>(Connection.java:332)
 at org.jboss.mq.SpyConnection.<init>(SpyConnection.java:66)
 at org.jboss.mq.SpyConnectionFactory.createConnection(SpyConnectionFactory.java:87)
 at ch.steria.tbazh.applet.TestApplet.listen(TestApplet.java:97)
 at ch.steria.tbazh.applet.TestApplet.init(TestApplet.java:34)
 at sun.applet.AppletPanel.run(Unknown Source)
 at java.lang.Thread.run(Unknown Source)

The exception is an inherited error. If I grant all permissions in the browsers java.policy, the Exception disapeares, but the connection goes up only on every 2. reload.

It happens with IE6 && Mozilla 1.6. I use JRE1.5 and JBoss 4.0.

 private void listen() throws JMSException, NamingException {
 initialContext = getInitialContext(getDocumentBase().getHost());
 TopicConnectionFactory topic = (TopicConnectionFactory)initialContext.lookup("ConnectionFactory");
 connection = topic.createConnection();
 // ^ here
 session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
 Destination destination = (Destination)initialContext.lookup("topic/testTopic");
 messageConsumer = session.createConsumer(destination);
 messageConsumer.setMessageListener(this);
 connection.start();
 }

If this is a bug, has somebody a workaround or knows an available patch?
Thanks in advance.

[adrian.brock]

More wild assertions.
The bug you link to has already been fixed in JBoss4.

The error message says you are missing a class.
I have no idea why the JDK in your browser isn't you telling the class that is missing?

But if you look at the source code,

org.jboss.mq.SpyJMSException.<init>(SpyJMSException.java:79)

http://cvs.sourceforge.net/viewcvs.py/jboss/jbossmq/src/main/org/jboss/mq/SpyJMSException.java?annotate=1.7
you will see it is NestedThrowable.Util which is in jboss-commons.jar

[umar]

Right. This bug is fixed. While debugging, I found this exception:

org.jboss.mq.SpyJMSException: Cannot disable the connection with the JMS server;
 - nested throwable: (java.io.IOException: Client is not connected)
 at org.jboss.mq.Connection.doStop(Connection.java:1289)
 at org.jboss.mq.Connection.stop(Connection.java:718)
 at ch.steria.tbazh.applet.TestApplet.stop(TestApplet.java:57)
 at sun.applet.AppletPanel.run(Unknown Source)
 at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: Client is not connected
 at org.jboss.mq.il.uil2.SocketManager.internalSendMessage(SocketManager.java:226)
 at org.jboss.mq.il.uil2.SocketManager.sendMessage(SocketManager.java:192)
 at org.jboss.mq.il.uil2.UILServerIL.setEnabled(UILServerIL.java:162)
 at org.jboss.mq.Connection.doStop(Connection.java:1285)
 ... 4 more

It only happens with more than one applet with the same code on a single webpage. I use now signed applets, the NoClassDefFoundError disapeared.
Before the reload, the applets are able to print JMS messages to stdout, so there are connections to JBossMQ.

I think there is a race condition in the connection code. The source of a demo applet, a html document and the necessary jars are available:
http://www.marti.nu/applet/
There is no JMS service running there. So the applet will not work.

Is this behavior reproducible and is it possible to fix it?
Thank you.

-Marti