Hi JBM experts, I have recently posted a similar question and it was resolved with the help of PeterJ: http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4224375#... However, while the standalone java client works fine. I run into NoClassDefFound Exception again when using the same code on Sun AS 8: Caused by: java.lang.NoClassDefFoundError at org.jboss.jms.client.delegate.ClientConnectionFactoryDelegate.createClient(ClientConnectionFactoryDelegate.java:298) at org.jboss.jms.client.delegate.ClientConnectionFactoryDelegate.org$jboss$jms$client$delegate$ClientConnectionFactoryDelegate$getClientAOPStack$aop(ClientConnectionFactoryDelegate.java:228) at org.jboss.jms.client.delegate.ClientConnectionFactoryDelegate.getClientAOPStack(ClientConnectionFactoryDelegate.java) at org.jboss.jms.client.delegate.ClientClusteredConnectionFactoryDelegate.org$jboss$jms$client$delegate$ClientClusteredConnectionFactoryDelegate$getClientAOPStack$aop(ClientClusteredConnectionFactoryDelegate.java:242) at org.jboss.jms.client.delegate.ClientClusteredConnectionFactoryDelegate.getClientAOPStack(ClientClusteredConnectionFactoryDelegate.java) at org.jboss.jms.client.ClientAOPStackLoader.load(ClientAOPStackLoader.java:75) at org.jboss.jms.client.JBossConnectionFactory.createConnectionInternal(JBossConnectionFactory.java:192) at org.jboss.jms.client.JBossConnectionFactory.createConnection(JBossConnectionFactory.java:87) at jmsremoteclient.TestMessageProducer.(TestMessageProducer.java:43) TestMessageProducer is the class where I try to initiate the connection to JBM. Obviously there may be class conflicts in the classpath...but the exception doesn't suggest the class name and therefore made it harder to debug. (I did included log4j.jar) Has anyone seem similar issue and have suggestions for the conflicting jar? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4224780#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...