MQSeries.net :: View topic - Classcast exception when receive pubsub message via MDB

DirkMaes · Posted: Fri Jun 08, 2007 2:41 am Post subject:

Hi,

We have a set up of Event Broker 5 in combination with WAS ND 6. We use Event Broker to perform pub/sub of multicast and unicast messages.

For the record: I have no knowledge of Event Broker
We are currently able to perform pub/sub operations via pure standalone java classes but we receive classcast exceptions when trying to listen for the same messages via a message driven bean.

The configuration

I created a message driven bean which implements the onMessage method like this:
public void onMessage(javax.jms.Message msg) {
System.out.println(msg.getClass().getName());
}

Quite simple as you can see.

As deployment descriptor we have

<message-driven id="CacheListener">
<ejb-name>CacheListener</ejb-name>
<ejb-class>com.fortis.be.s06.dnfo.common.cache.framework.ejb.CacheListenerBean</ejb-class>
<transaction-type>Container</transaction-type>
<message-driven-destination>
<destination-type>javax.jms.Topic</destination-type>
<subscription-durability>NonDurable</subscription-durability>
</message-driven-destination>
</message-driven>

Plus we have defined the transation settings as follow

<container-transaction>
<method>
<ejb-name>CacheListener</ejb-name>
<method-name>onMessage</method-name>
<method-params>
<method-param>javax.jms.Message</method-param>
</method-params>
</method>
<trans-attribute>NotSupported</trans-attribute>
</container-transaction>

I configured a message listener port with the default settings and added the custom property NON.ASF.RECEIVE.TIMEOUT=10

I configured a WebSphere MQ topic connection factory where a set the parameters
host, port
transport type to DIRECT
enable multicast transport to DISABLED

The settings for the WebSphere MQ topic destination are
Non persistent, target client = JMS and Enable multicast transport = DISABLED

The behaviour
First of all our application no longer start correctly when we start the application server. The following error is received (during the last steps of the startup):

MDBListenerIm I WMSG0043I: MDB Listener CacheListenerPort stopped for JMSDestination dnfo/unicast/topic/cache
MDBListenerIm I WMSG0058I: Listener Port CacheListenerPort will attempt to restart in 60 seconds
ApplicationMg E WSVR0101W: An error occurred starting, BE_FORTIS_DNFO-ServerEar
ApplicationMg A WSVR0217I: Stopping application: BE_FORTIS_DNFO-ServerEar

When we restart the application manually (while the server is already running). The application starts without a problem.

When we publish a message via a standalone java client we always receive a classcast exception

[08/06/07 11:27:52:083 CEST] 00000031 LocalTranCoor E WLTC0017E: Resources rolled back due to setRollbackOnly() being called.
[08/06/07 11:27:52:442 CEST] 00000030 SystemOut O INSIDE EJBCREATE of CACHELISTENERBEAN
[08/06/07 11:27:52:442 CEST] 00000030 ServerSession W WMSG0031E: Exception processing JMS Message for MDB CacheListener, JMSDestination dnfo/unicast/topic/cache : java.lang.ClassCastException: com.fortis.be.s06.dnfo.common.cache.framework.ejb.CacheListenerBean
at com.ibm.ejs.jms.listener.ServerSession.contact admin(ServerSession.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.onMessage(ServerSession.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.dispatch(ServerSession.java(Inlined Compiled Code))
at sun.reflect.GeneratedMethodAccessor29.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSessionDispatcher.dispatch(ServerSessionDispatcher.java(Compiled Code))
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java(Compiled Code))
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.run(ServerSession.java(Compiled Code))
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1471)

[08/06/07 11:27:53:458 CEST] 00000030 ExceptionUtil E CNTR0020E: EJB threw an unexpected (non-declared) exception during invocation of method "onMessage" on bean "BeanId(BE_FORTIS_DNFO-ServerEar#BE_FORTIS_DNFO-EjbCommon.jar#CacheListener, null)". Exception data: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor29.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSessionDispatcher.dispatch(ServerSessionDispatcher.java(Compiled Code))
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java(Compiled Code))
at com.ibm.ejs.container.MDBWrapper.onMessage(MDBWrapper.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.run(ServerSession.java(Compiled Code))
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1471)
Caused by: java.lang.ClassCastException: com.fortis.be.s06.dnfo.common.cache.framework.ejb.CacheListenerBean
at com.ibm.ejs.jms.listener.ServerSession.contact admin(ServerSession.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.onMessage(ServerSession.java(Compiled Code))
at com.ibm.ejs.jms.listener.ServerSession.dispatch(ServerSession.java(Inlined Compiled Code))
... 8 more

I have the impression that we are not yet inside the onMessage method of our bean but that the failure happens before the actual call to our method.

Is there something that we have forgotten to configure? Do I have to configure something specifically on Event Broker for this to work?

I wasnÂ¡Â¦t able to find a good document that explained the configuration for using MDB in combination with Event Broker multicast/unicast.

Version of WAS is:

Name IBM WebSphere Application Server
Version 6.0.2.17
ID BASE
Build Level cf170648.10
Build Date 11/29/06

Thanks a lot for you input. I certainly need it Æ’Âº

Dirk