Hello, We are using JbossCache in a clustered environment. (JBoss, Ibatis, Oracle). We are unable to figure out the reason for an exception when the JBossCacheService tries to do replication on the other node. [java.io.NotSerializableException: java.lang.Object] We have ensured that all the objects stored in Collections implement the Serializable interface. Following is the detailed stack trace. -------------------------------------------------------------------------------------- 09:57:47,393 INFO [STDOUT] java.io.NotSerializableException: java.lang.Object 09:57:47,393 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1054) 09:57:47,393 INFO [STDOUT] at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1332) 09:57:47,393 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1304) 09:57:47,393 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1332) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1304) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1332) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1304) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1332) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1304) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:278) 09:57:47,409 INFO [STDOUT] at java.util.ArrayList.writeObject(ArrayList.java:529) 09:57:47,409 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 09:57:47,409 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 09:57:47,409 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 09:57:47,409 INFO [STDOUT] at java.lang.reflect.Method.invoke(Method.java:324) 09:57:47,409 INFO [STDOUT] at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:809) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1296) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:278) 09:57:47,409 INFO [STDOUT] at java.util.HashMap.writeObject(HashMap.java:978) 09:57:47,409 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 09:57:47,409 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 09:57:47,409 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 09:57:47,409 INFO [STDOUT] at java.lang.reflect.Method.invoke(Method.java:324) 09:57:47,409 INFO [STDOUT] at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:809) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1296) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1247) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1052) 09:57:47,409 INFO [STDOUT] at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:278) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.SessionBasedClusteredSession.writeExternal(SessionBasedClusteredSession.java:288) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.JBossCacheService.externalizeSession(JBossCacheService.java:771) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.JBossCacheService.putSession(JBossCacheService.java:229) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.SessionBasedClusteredSession.processSessionRepl(SessionBasedClusteredSession.java:165) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.JBossCacheManager.processSessionRepl(JBossCacheManager.java:606) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.JBossCacheManager.storeSession(JBossCacheManager.java:375) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.InstantSnapshotManager.snapshot(InstantSnapshotManager.java:38) 09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.tc5.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:91)09:57:47,409 INFO [STDOUT] at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:59) 09:57:47,409 INFO [STDOUT] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126) 09:57:47,409 INFO [STDOUT] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105) 09:57:47,409 INFO [STDOUT] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107) 09:57:47,409 INFO [STDOUT] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148) 09:57:47,409 INFO [STDOUT] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856) 09:57:47,409 INFO [STDOUT] at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744) 09:57:47,409 INFO [STDOUT] at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527) 09:57:47,409 INFO [STDOUT] at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112) 09:57:47,409 INFO [STDOUT] at java.lang.Thread.run(Thread.java:534) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3959962#... 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