GetObject() on Object Message hangs

Question

          Hi all,
          I have a simple MDB listening on a queue for object messages. These object messages
          contain custom java objects created using castor-0.9.3.9. The application gets deployed
          successfully and i send an message from a test class outside the bea environment.
          On sending a message, this is is what i see on the server window:
          NotificationListener : Got the Object Message
          NotificationListener : Going in for casting object
          And it hangs at that.
          The code in the NotificationListener class is as follows:
          // // Implementation of MessageListener // //
          public void onMessage(Message msg) {
          ObjectMessage ObjMessage = null;
          Notification objNotification = null;
          // get object message
          ObjMessage = (ObjectMessage) msg;
          print("Got the Object Message");
          // extract the notification
          try {
               print("Going in for casting object");
          objNotification = (Notification)ObjMessage.getObject();
          print("Got Notification from Message");
          catch(Exception ex) {
          print("Could not extract Notification from Object Message.");
               print("Exception : " + ex);
          The message after the line where i try to fetch it and type cast does not get printed.
          My custom classes are in the classpath ONLY and not in the deployed ear.
          Any help regarding this problem would me most welcome.
          Cheers,
          Anjan
          

Answer 1

Hello,
          I agree, you need to catch Throwable to capture all exceptions (checked
          and unchecked). Although I do have a few observations:
          1. Do not assume you are getting an Object that you want, check first if
          the object you want is of the type you are looking for, use instanceof.
          Using instanceof my sound expense but it is cheap (I ran a million
          instanceof and found on average the time in milliseconds for each instance
          of command was less than 1 if memory serves :-).
          2. Since you are using, sending, a java object your object will get
          serialized and de-serialized and this could be very expensive and time
          consuming depending now how complex the java object is. I have seen the
          cost for serialization run up to 1 second per object when using JMS.
          3. Test you MDB by sending a simple object and see if that causes the same
          hanging problem, if not then you can be assured there is a problem with
          getting access to the serialized object.
          4. I do not know, and am too lazy to look at the WLS code, if when
          requesting an object from message object the de-serialization is done only
          when you ask for it or at the time the message is received (do not know if
          this makes a difference, just an observation :-)
          Hope that helps ...
          Douglas WF Acheson
          "Adarsh Dattani" <[email protected]> wrote in message
          news:[email protected]...
          > Catch Throwable instead of Exception and then post the results.
          > Adarsh
          >
          > "Anjan Rao" <[email protected]> wrote in message
          > news:[email protected]...
          > >
          > > Hi all,
          > > I have a simple MDB listening on a queue for object messages. These
          > object messages
          > > contain custom java objects created using castor-0.9.3.9. The
          application
          > gets deployed
          > > successfully and i send an message from a test class outside the bea
          > environment.
          > >
          > > On sending a message, this is is what i see on the server window:
          > > -----------------------------------------------------------------
          > > NotificationListener : Got the Object Message
          > > NotificationListener : Going in for casting object
          > >
          > > And it hangs at that.
          > >
          > > The code in the NotificationListener class is as follows:
          > > ---------------------------------------------------------
          > > // // Implementation of MessageListener // //
          > > public void onMessage(Message msg) {
          > > ObjectMessage ObjMessage = null;
          > > Notification objNotification = null;
          > >
          > > // get object message
          > > ObjMessage = (ObjectMessage) msg;
          > > print("Got the Object Message");
          > >
          > > // extract the notification
          > > try {
          > > print("Going in for casting object");
          > > objNotification = (Notification)ObjMessage.getObject();
          > > print("Got Notification from Message");
          > > }
          > > catch(Exception ex) {
          > > print("Could not extract Notification from Object Message.");
          > > print("Exception : " + ex);
          > > }
          > >
          > >
          > >
          > > The message after the line where i try to fetch it and type cast does
          not
          > get printed.
          > >
          > > My custom classes are in the classpath ONLY and not in the deployed ear.
          > >
          > > Any help regarding this problem would me most welcome.
          > >
          > > Cheers,
          > > Anjan
          >
          >