The stack trace you sent is JavaSerialization. (see.... at org.jboss.remoting.serialization.impl.java.JavaSerializationManager.receiveObject(JavaSerializationManager.java:128) ) package names for JBossSerialization are starting with org.jboss.serial.... You would need to configure your remoting layer to use JBossSerialization if you want to test this with JBoss Serialization. I know that there are a couple of issues with JBossRemoting when using Mustang with regular Java Serialization. Tom Elrod (Project lead for JBoss Remoting) is working on it. Something about some change with ClassLoading operations on Mustang: http://cruisecontrol.jboss.com/cc/artifacts/jboss-remoting-testsuite-1.6/... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3964686#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...