Distributed Cache Synchronization

Question

I'm trying to implement distributed cache synchronization via RMI but I find the documentation to be very limited on how to do this. I'm doing exactly what the documentation says and I end up with a CommunicationException when trying to connect to the pre-existing session. The toplink docs are not very descriptive about the cause or meaning of CommunicationException.
Also, this is in toplink 3.6 which I know is old, but comparing it with the new oracle versions the requirements for DCS are almost identical.
Here is the code I'm trying to use:
          RMIRemoteSessionController controller = (RMIRemoteSessionController)Naming.lookup(registryName);
          RemoteConnection connection = new RMIConnection(controller);
          CacheSynchronizationManager syncMgr = new CacheSynchronizationManager();
          serverSession.setCacheSynchronizationManager(syncMgr);
          serverSession.getCacheSynchronizationManager().addRemoteConnection(connection);
Here is the stack trace I'm seeing:
18:53:01,146 DEBUG OEDataEntry - OEDataEntry - - EXCEPTION [TOPLINK-0] (3.6.2 JDK1.2): TOPLink.Public.Remote.CommunicationException
18:53:01,146 DEBUG OEDataEntry - OEDataEntry - - EXCEPTION DESCRIPTION: Error Sending connection service to
18:53:01,156 DEBUG OEDataEntry - OEDataEntry - - INTERNAL EXCEPTION: java.lang.ClassCastException
18:53:01,166 DEBUG OEDataEntry - OEDataEntry - -      at TOPLink.Public.Remote.CacheSynchronizationManager.addRemoteConnectionForSynchronization(CacheSynchronizationManager.java:84)
18:53:01,166 DEBUG OEDataEntry - OEDataEntry - -      at TOPLink.Public.Remote.CacheSynchronizationManager.addRemoteConnection(CacheSynchronizationManager.java:68)

Answer 1

Also, if someone could provide me with a complete example of how to implement distributed cache synchronization via RMI that would be helpful too, the docs are very sparse on this.
Basically what I'm trying to do is this: I have a web application that uses toplink to connect to a database. I have a separate application that also uses toplink to connecto the database that runs outside the application. The external app can update tables that the web application uses, I would like the web application to have it's cache updated when the external app changes something in those tables. It is my understanding that this is what distributed cache synchronization is for. How do I use it?