Propagating User Transactions

Question

Hi,
I am trying to check how user transactions work in context of the OC4j Containers.
I have deployed a Stateless Session Bean in the 'standalone' OC4J container of JDev10.1.3. I then exposed the EJB as a WebService.
Next, I wrote a client and am running it in the 'embedded' OC4J container of JDev 10.1.3. From this client, I am trying to invoke the bean methods as WebService calls. Below is my client code:
<code>
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.evermind.server.rmi.RMIInitialContextFactory");
env.put(Context.PROVIDER_URL, "ormi://localhost:23791/");
env.put(Context.SECURITY_PRINCIPAL, "oc4jadmin");
env.put(Context.SECURITY_CREDENTIALS, "welcome");
Context context = new InitialContext(env);
ut = (UserTransaction) context.lookup("java:comp/UserTransaction");
ut.begin();
// call bean methods.
ut.commit();
</code>
However, I am not able to look up the JNDI Name for UserTransaction in the embedded OC4J. I tried both "java:comp/UserTransaction" and "jta/usertransaction".
Could somebody please let me know how to lookup the User Transaction from the Context in OC4J?
Also, I read somewhere that UserTransactions (begin .. method .. commit/rollback) is not supported in OC4J unless the EJB are running in the same container? Is this true? In which case, my above test scenario would never work, is it?
Many thanks in Advance.
Regards,
Pratul

Answer 1

Hi Katalin!
Thanks a lot for your reply.
You are right. The port 23891 is the correct port for ORMI for embedded OC4J.
Actually, I was trying to execute the client as a standalone Java class (public static void main() ). I eventually moved my client code to a JSP and was able to retrieve the UserTransaction object using "java:comp/UserTransaction".
I found this strange since I have tested transaction boundaries in a similar fashion using WSAD and it worked just fine. The only reason I could think of was that the classloader in JDeveloper was not able to load the complete environment implementations of the transactions, before the lookup call is made from my code.
However, now after having moved my client code into a JSP, the UserTransaction object retrieved is "com.sun.enterprise.distributedtx.UserTransactionImpl".
And when I invoke the begin() method on this transaction object, I get a NullPointerException. :((
06/10/03 15:31:07 java.lang.NullPointerException
06/10/03 15:31:07      at com.sun.jts.jta.TransactionManagerImpl.begin(TransactionManagerImpl.java:171)
06/10/03 15:31:07      at com.sun.jts.jta.UserTransactionImpl.begin(UserTransactionImpl.java:50)
06/10/03 15:31:07      at com.sun.enterprise.distributedtx.UserTransactionImpl.begin(UserTransactionImpl.java:66)
Does anybody have any idea why that particular reference of the UserTransaction object is returned? Is it because of any extra/missing jar files in the classpath? Why a NullPointerException , even when the object itself is not null ?
Please help !!
Thanks,
Pratul