Clustering TopLink with 10g

Question

We are trying to use TopLink (version 9.0.4.3) in a cluster of Oracle 10g application servers (9.0.4.0.0) but we are having a number of issues getting it to work. When I add the following into the sessions.xml file I get a number of toplink errors on startup:
<cache-synchronization-manager>
<clustering-service>
oracle.toplink.remote.rmi.RMIJNDIClusteringService
</clustering-service>
<jndi-user-name>userName</jndi-user-name>
<jndi-password>password</jndi-password>
<naming-service-initial-context-factory-name>
oracle.com.evermind.server.rmi.RMIInitialContextFactory
</naming-service-initial-context-factory-name>
<naming-service-url>ormi://hostname:23791/appName</naming-service-url>
</cache-synchronization-manager>
The errors that we get are:
Exception Description: Several [5] SessionLoaderExceptions were thrown:
Exception [TOPLINK-9003] (OracleAS TopLink - 10g (9.0.4) (Build 031126)): oracle.toplink.exceptions.SessionLoaderException
Exception Description: Unable to process XML tag [clustering-service] with value [
oracle.toplink.remote.rmi.RMIJNDIClusteringService
Internal Exception: java.lang.ClassNotFoundException:
oracle.toplink.remote.rmi.RMIJNDIClusteringService
Exception [TOPLINK-9003] (OracleAS TopLink - 10g (9.0.4) (Build 031126)): oracle.toplink.exceptions.SessionLoaderException
Exception Description: Unable to process XML tag [jndi-user-name] with value [admin].
Internal Exception: java.lang.NullPointerException
Exception [TOPLINK-9003] (OracleAS TopLink - 10g (9.0.4) (Build 031126)): oracle.toplink.exceptions.SessionLoaderException
Exception Description: Unable to process XML tag [jndi-password] with value [XXX].
Internal Exception: java.lang.NullPointerException
Exception [TOPLINK-9003] (OracleAS TopLink - 10g (9.0.4) (Build 031126)): oracle.toplink.exceptions.SessionLoaderException
Exception Description: Unable to process XML tag [naming-service-initial-context-factory-name] with value [
oracle.com.evermind.server.rmi.RMIInitialContextFactory
Internal Exception: java.lang.NullPointerException
Exception [TOPLINK-9003] (OracleAS TopLink - 10g (9.0.4) (Build 031126)): oracle.toplink.exceptions.SessionLoaderException
Exception Description: Unable to process XML tag [naming-service-url] with value [ormi://localhost:23791/XXX].
Internal Exception: java.lang.NullPointerException
All feedback is appreciated,
Marc

Answer 1

There was a recent thread on this issue,
Missing Descriptor in Servlet
Basically TopLink does not get notified of the undeployment of an app, so cannot remove the session from the SessionManager. (unless you are using CMP)
If you can receive notification of the deploy/undeploy you could remove or refresh the session from the session manager.
A simple way to do this would be to keep a static boolean variable in your apps class that accesses the session from the session manager. The first time you access the session refresh it and set the static to true.
To refresh a session from the session manager use the API,
SessionManager.getSession(XMLSessionConfigLoader/XMLLoader xmlLoader, String sessionName, ClassLoader classLoader, boolean shouldLoginSession, boolean shouldRefreshSession)
i.e.
SessionManager.getManager().getSession(new XMLSessionConfigLoader/XMLLoader("sessions.xml/or your file name/path"), "yourSessionName", yourClassLoader, true, true);
Only use this API the first time you access the session from the app.
You can also use the following code to remove a session,
SessionManager.getManager().getSessions().remove("yourSessionName");
I have logged this issue internally, hopefully a better solution will be provided in the 10.1.3 release.