Hello, We have encountered a serialization problem when we moved to JDK 1.6. The following EJB throws an exception (Below). public class TestServiceBean implements TestService { @TransactionAttribute(TransactionAttributeType.REQUIRED) public Format getFormat() { return DateFormat.getDateInstance(DateFormat.SHORT); } } The code works perfectly in 1.5. We tried the latest nightly build of Mustang to no avail. Peforming a deep clone to the same object locally works fine thus leading us to believe that the interaction with JBOSS is what is causing this problem. We are using 4.0.4 JA on linux. Thanks for any info. Caused by: java.rmi.MarshalException: Failed to communicate. Problem during marshalling/unmarshalling; nested exception is: java.io.StreamCorruptedException: invalid type code: 00 at org.jboss.remoting.transport.socket.SocketClientInvoker.transport(SocketClientInvoker.java:306) at org.jboss.remoting.RemoteClientInvoker.invoke(RemoteClientInvoker.java:143) at org.jboss.remoting.Client.invoke(Client.java:525) at org.jboss.remoting.Client.invoke(Client.java:488) at org.jboss.aspects.remoting.InvokeRemoteInterceptor.invoke(InvokeRemoteInterceptor.java:55) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98) at org.jboss.aspects.tx.ClientTxPropagationInterceptor.invoke(ClientTxPropagationInterceptor.java:61) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98) at org.jboss.aspects.security.SecurityClientInterceptor.invoke(SecurityClientInterceptor.java:55) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98) at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInterceptor.java:65) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98) at org.jboss.ejb3.stateless.StatelessRemoteProxy.invoke(StatelessRemoteProxy.java:102) ... 2 more Caused by: java.io.StreamCorruptedException: invalid type code: 00 at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1356) at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1642) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1323) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1945) at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:480) at java.util.Calendar.readObject(Calendar.java:2609) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1846) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1945) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1869) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351) at org.jboss.aop.joinpoint.InvocationResponse.readExternal(InvocationResponse.java:107) at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1792) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1751) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1945) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1869) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351) at org.jboss.remoting.serialization.impl.java.JavaSerializationManager.receiveObject(JavaSerializationManager.java:128) at org.jboss.remoting.marshal.serializable.SerializableUnMarshaller.read(SerializableUnMarshaller.java:66) at org.jboss.remoting.transport.socket.SocketClientInvoker.transport(SocketClientInvoker.java:279) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3964666#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...