Toplink Optimistic Locking not working with Session Bean facade.

Question

I am working on Oracle JDeveloper v 10.1.2 and connecting to an Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit
The application is based on J2EE architecture and the technology stack uses Struts for presentation/controller framework, Stateless Session EJBs as session facade for custom business services, Simple java classes for the business services, Toplink implementation of DAO layer, Domain objects are mapped to database tables using Toplink Workbench that ships with JDeveloper. The transaction is managed by the session bean and hence the toplink session is configured to use external transaction controller and a named datasource as follows.
<session xsi:type="server-session">
<name>DBSession</name>
<server-platform xsi:type="oc4j-1012-platform"/>
<event-listener-classes/>
<logging xsi:type="toplink-log">
<log-level>fine</log-level>
<file-name>D:/ToplinkLog.log</file-name>
</logging>
<primary-project xsi:type="xml">META-INF/toplink-descriptor.xml</primary-project>
<login xsi:type="database-login">
<platform-class>oracle.toplink.platform.database.oracle.Oracle10Platform</platform-class>
<external-connection-pooling>true</external-connection-pooling>
<external-transaction-controller>true</external-transaction-controller>
<sequencing>
<default-sequence xsi:type="native-sequence">
<name>Native</name>
<preallocation-size>1</preallocation-size>
</default-sequence>
</sequencing>
<datasource>jdbc/ORADS</datasource>
</login>
</session>
We intend to use Optimistic Locking based on Timestamp-version locking through an audit field "last_modification_date" of type java.sql.Timestamp. The corresponding database field is also of type Timestamp(6). We are not storing the version in cache.
The problem we are facing is as follows.. we have an edit screen from where user can edit values for a domain object which are then persisted using Toplink...we expect Toplink to check the database record version (modification_date timestamp) before it applies the update. In DAO implementation, we register the object in a unitOfWork, then set the modified values, however we leave the modification_date (version field) unedited. Now when the application is running, on edit, an exception is thrown by the Session bean before ending the transaction.
com.evermind.server.rmi.OrionRemoteException: Transaction was rolled back: Error in transaction: java.lang.NullPointerException
     at TrackingMediator_StatelessSessionBeanWrapper2.editOverheadExpenditure(TrackingMediator_StatelessSessionBeanWrapper2.java:1597)
     at com.enbridge.dsm.web.action.TrackingPortfolioAction.editOverheadExpenditure(TrackingPortfolioAction.java:264)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java)
     at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:278)
     at com.enbridge.dsm.web.shared.BaseAction.execute(BaseAction.java:90)
     at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:465)
     at com.enbridge.dsm.web.shared.DSMPojoRequestProcessor.process(DSMPojoRequestProcessor.java:182)
     at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1425)
     at com.sourcebeat.strutslive.common.SLActionServlet.process(SLActionServlet.java:44)
     at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at com.evermind.server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:65)
     at oracle.security.jazn.oc4j.JAZNFilter.doFilter(Unknown Source)
     at com.evermind.server.http.EvermindFilterChain.doFilter(EvermindFilterChain.java:16)
     at com.enbridge.dsm.web.shared.security.SecurityFilter.doFilter(SecurityFilter.java:142)
     at com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:645)
     at com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:322)
     at com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:790)
     at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:270)
     at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:112)
     at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:192)
     at java.lang.Thread.run(Thread.java:534)
     Nested exception is:
java.lang.NullPointerException
     at oracle.jdbc.driver.PhysicalConnection.commit(PhysicalConnection.java:1190)
     at com.evermind.sql.FilterConnection.commit(FilterConnection.java:209)
     at com.evermind.sql.DriverManagerXAConnection.commit(DriverManagerXAConnection.java:203)
     at com.evermind.server.TransactionEnlistment.commit(TransactionEnlistment.java:251)
     at com.evermind.server.ApplicationServerTransaction.singlePhaseCommit(ApplicationServerTransaction.java:745)
     at com.evermind.server.ApplicationServerTransaction.commit(ApplicationServerTransaction.java:690)
     at com.evermind.server.ApplicationServerTransaction.end(ApplicationServerTransaction.java:1035)
     at TrackingMediator_StatelessSessionBeanWrapper2.editOverheadExpenditure(TrackingMediator_StatelessSessionBeanWrapper2.java:1593)
     at com.enbridge.dsm.web.action.TrackingPortfolioAction.editOverheadExpenditure(TrackingPortfolioAction.java:264)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java)
     at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:278)
     at com.enbridge.dsm.web.shared.BaseAction.execute(BaseAction.java:90)
     at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:465)
     at com.enbridge.dsm.web.shared.DSMPojoRequestProcessor.process(DSMPojoRequestProcessor.java:182)
     at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1425)
     at com.sourcebeat.strutslive.common.SLActionServlet.process(SLActionServlet.java:44)
     at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at com.evermind.server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:65)
     at oracle.security.jazn.oc4j.JAZNFilter.doFilter(Unknown Source)
     at com.evermind.server.http.EvermindFilterChain.doFilter(EvermindFilterChain.java:16)
     at com.enbridge.dsm.web.shared.security.SecurityFilter.doFilter(SecurityFilter.java:142)
     at com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:645)
     at com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:322)
     at com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:790)
     at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:270)
     at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:112)
     at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:192)
     at java.lang.Thread.run(Thread.java:534)
Note that the exception is thrown at the time when the session bean is about to commit the transaction. i.e. the DAO code did not throw any exception and was able to check the optimistic locking and submit the update transaction.
I am not able to understand why is the the EJB throwing this weird error with Optimistic locking implementation. The application is working fine when the optimistic locking is disabled.
I am facing another problem due to this problem... since the session bean throws this exception after exiting the bean implemented method, when trying to commit the transaction, I am not able to mark the session context to setRollbackOnly. Hence if I continue on to another transaction by navigating to another screen in the application, mysteriously the previous transaction gets committed!!... again... weird...

Answer 1

I am using JDBC driver version 10.1.2.
I saw this additional error message in JDeveloper console, which for some reason was not logged to my log4j log file... if it helps...
06/09/22 18:32:10 Thr[thread 6]-TransactionEnlistment.TransactionEnlistment.Caught forgetandRollback XAException e null
Here are the logs from my Toplink log file....
[TopLink Info]: 2006.09.22 06:31:46.546--ServerSession(989)--Thread(Thread[HttpRequestHandler-86,5,main])--TopLink, version: Oracle TopLink - 10g Release 3 (10.1.3.0.0) (Build 060118)
[TopLink Info]: 2006.09.22 06:31:46.578--ServerSession(989)--Thread(Thread[HttpRequestHandler-86,5,main])--Server: Oracle Application Server Containers for J2EE 10g (10.1.2.0.0)
[TopLink Config]: 2006.09.22 06:31:46.593--ServerSession(989)--Connection(991)--Thread(Thread[HttpRequestHandler-86,5,main])--connecting(DatabaseLogin(
     platform=>Oracle10Platform
     user name=> ""
     connector=>JNDIConnector datasource name=>jdbc/ORADS
[TopLink Config]: 2006.09.22 06:31:47.484--ServerSession(989)--Connection(1432)--Thread(Thread[HttpRequestHandler-86,5,main])--Connected: jdbc:oracle:thin:@10.210.16.37:1521:orabld
     User: APP_USR
     Database: Oracle Version: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
     Driver: Oracle JDBC driver Version: 10.1.0.3.0
[TopLink Config]: 2006.09.22 06:31:47.500--ServerSession(989)--Connection(1433)--Thread(Thread[HttpRequestHandler-86,5,main])--connecting(DatabaseLogin(
     platform=>Oracle10Platform
     user name=> ""
     connector=>JNDIConnector datasource name=>jdbc/ORADS
[TopLink Config]: 2006.09.22 06:31:47.500--ServerSession(989)--Connection(1434)--Thread(Thread[HttpRequestHandler-86,5,main])--Connected: jdbc:oracle:thin:@10.210.16.37:1521:orabld
     User: APP_USR
     Database: Oracle Version: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
     Driver: Oracle JDBC driver Version: 10.1.0.3.0
[TopLink Info]: 2006.09.22 06:31:47.671--ServerSession(989)--Thread(Thread[HttpRequestHandler-86,5,main])--DBSession login successful
[TopLink Fine]: 2006.09.22 06:31:47.703--ServerSession(989)--Connection(1554)--Thread(Thread[HttpRequestHandler-86,5,main])--select * from user_role ur, app_resource ar, role_resource rr where rr.APP_RESOURCE_ID = ar.APP_RESOURCE_ID and rr.USER_ROLE_ID = ur.USER_ROLE_ID
[TopLink Fine]: 2006.09.22 06:31:49.937--ServerSession(989)--Connection(10245)--Thread(Thread[HttpRequestHandler-86,5,main])--SELECT * FROM PROGRAM_SUB_CAT
[TopLink Fine]: 2006.09.22 06:31:50.015--ServerSession(989)--Connection(10332)--Thread(Thread[HttpRequestHandler-86,5,main])--SELECT PROGRAM_ID, CREATED_BY_USERID FROM (SELECT CREATED_BY_USERID, ROWNUM PROGRAM_ID FROM (SELECT DISTINCT(CREATED_BY_USERID) CREATED_BY_USERID, 1 AS PROGRAM_ID FROM PROGRAM))
(I only see my application specific queries after this... no exceptions or debug logs)... as I said before.. the application gives exception in the session bean at the time of commit, and there's no exception raised from Toplink code in DAO...