I'm returning a rather deep and complex object structure from an ejb3 stateless session bean to another, deployed in two different ears. The initiating bean is annotated with JSR-181 WS annotations. I'm running on 4.0.4.GA with jdk1.5.0_08 and have tried with both serialization 1.0.1 and 1.0.2. On returning from the session bean I get the following exception. Any ideas to what the cause may be or what I can do to further investigate? java.lang.reflect.UndeclaredThrowableException at $Proxy467.findBookings(Unknown Source) at net.mysys.webservice.booking.RetrieveReservationBusiness.retrieveBookings(RetrieveReservationBusiness.java:61) at net.mysys.webservice.booking.BookingFacadeBean.retrieveReservation(BookingFacadeBean.java:57) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:112) at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:166) at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:79) at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:197) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:62) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:78) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:47) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.stateless.StatelessContainer.localInvoke(StatelessContainer.java:181) at org.jboss.ejb3.stateless.StatelessContainer.localInvoke(StatelessContainer.java:147) at org.jboss.ws.integration.jboss.ServiceEndpointInvokerEJB3.invokeServiceEndpoint(ServiceEndpointInvokerEJB3.java:126) at org.jboss.ws.server.ServiceEndpointInvoker.invoke(ServiceEndpointInvoker.java:115) at org.jboss.ws.server.ServiceEndpoint.handleRequest(ServiceEndpoint.java:219) at org.jboss.ws.server.ServiceEndpointManager.processSOAPRequest(ServiceEndpointManager.java:355) at org.jboss.ws.server.StandardEndpointServlet.doPost(StandardEndpointServlet.java:115) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.jboss.ws.server.StandardEndpointServlet.service(StandardEndpointServlet.java:76) at javax.servlet.http.HttpServlet.service(HttpServlet.java:810) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105) at org.apache.catalina.valves.FastCommonAccessLogValve.invoke(FastCommonAccessLogValve.java:495) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527) at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112) at java.lang.Thread.run(Thread.java:595) Caused by: java.io.IOException at org.jboss.serial.persister.RegularObjectPersister.readSlotWithMethod(RegularObjectPersister.java:107) at org.jboss.serial.persister.RegularObjectPersister.defaultRead(RegularObjectPersister.java:269) at org.jboss.serial.persister.RegularObjectPersister.readData(RegularObjectPersister.java:241) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) at org.jboss.serial.objectmetamodel.DataContainer$DataContainerInput.readObject(DataContainer.java:836) at org.jboss.serial.io.MarshalledObjectForLocalCalls.get(MarshalledObjectForLocalCalls.java:60) at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInterceptor.java:61) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101) at org.jboss.ejb3.stateless.StatelessRemoteProxy.invoke(StatelessRemoteProxy.java:102) ... 57 more Caused by: java.lang.reflect.InvocationTargetException 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:585) at org.jboss.serial.persister.RegularObjectPersister.readSlotWithMethod(RegularObjectPersister.java:103) ... 66 more Caused by: org.jboss.serial.exception.SerializationException: Could not create instance of java.util.HashMap$Values - java.util.HashMap$Values at org.jboss.serial.classmetamodel.ClassMetaData.newInstance(ClassMetaData.java:342) at org.jboss.serial.persister.RegularObjectPersister.readData(RegularObjectPersister.java:239) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) at org.jboss.serial.objectmetamodel.DataContainer$DataContainerInput.readObject(DataContainer.java:836) at org.jboss.serial.persister.RegularObjectPersister.readSlotWithFields(RegularObjectPersister.java:353) at org.jboss.serial.persister.RegularObjectPersister.defaultRead(RegularObjectPersister.java:273) at org.jboss.serial.persister.RegularObjectPersister.readData(RegularObjectPersister.java:241) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) at org.jboss.serial.objectmetamodel.DataContainer$DataContainerInput.readObject(DataContainer.java:836) at org.jboss.serial.persister.ObjectInputStreamProxy.readObjectOverride(ObjectInputStreamProxy.java:68) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:343) at java.util.ArrayList.readObject(ArrayList.java:591) ... 71 more Caused by: java.lang.InstantiationException: java.util.HashMap$Values at java.lang.Class.newInstance0(Class.java:335) at java.lang.Class.newInstance(Class.java:303) at org.jboss.serial.classmetamodel.ClassMetaData.newInstance(ClassMetaData.java:334) ... 84 more View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3970837#... 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