Stateful session bean, return objects

Question

I have a stateful session bean deployed on glassfish, and have a method called getCars which returns Collection of objects of Car class. Car class is defined in bean project and in client project(actually it is the same class). I have a client(not application client) in which I obtain the reference to bean remote interface as described here. But my client craches with such exceptions

Exception in thread "main" javax.ejb.EJBException: java.rmi.MarshalException: CORBA BAD_PARAM 1330446342 Maybe; nested exception is: 
        java.io.NotSerializableException: ----------BEGIN server-side stack trace----------
org.omg.CORBA.BAD_PARAM:   vmcid: OMG  minor code: 6 completed: Maybe
        at com.sun.corba.ee.impl.logging.OMGSystemException.notSerializable(OMGSystemException.java:990)
        at com.sun.corba.ee.impl.logging.OMGSystemException.notSerializable(OMGSystemException.java:1005)
        at com.sun.corba.ee.impl.orbutil.ORBUtility.throwNotSerializableForCorba(ORBUtility.java:753)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.write_abstract_interface(CDROutputStream_1_0.java:765)
        at com.sun.corba.ee.impl.encoding.CDROutputObject.write_abstract_interface(CDROutputObject.java:709)
        at com.sun.corba.ee.impl.javax.rmi.CORBA.Util.writeAbstractObject(Util.java:501)
        at com.sun.corba.ee.impl.io.IIOPOutputStream.writeObjectOverride(IIOPOutputStream.java:197)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
        at java.util.ArrayList.writeObject(ArrayList.java:570)
        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 com.sun.corba.ee.impl.io.IIOPOutputStream.invokeObjectWriter(IIOPOutputStream.java:760)
        at com.sun.corba.ee.impl.io.IIOPOutputStream.outputObject(IIOPOutputStream.java:716)
        at com.sun.corba.ee.impl.io.IIOPOutputStream.simpleWriteObject(IIOPOutputStream.java:227)
        at com.sun.corba.ee.impl.io.ValueHandlerImpl.writeValueInternal(ValueHandlerImpl.java:268)
        at com.sun.corba.ee.impl.io.ValueHandlerImpl.writeValueWithVersion(ValueHandlerImpl.java:240)
        at com.sun.corba.ee.impl.io.ValueHandlerImpl.writeValue(ValueHandlerImpl.java:193)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.callWriteValue(CDROutputStream_1_0.java:932)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.writeRMIIIOPValueType(CDROutputStream_1_0.java:917)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.write_value(CDROutputStream_1_0.java:1044)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.write_value(CDROutputStream_1_0.java:1057)
        at com.sun.corba.ee.impl.encoding.CDROutputStream_1_0.write_value(CDROutputStream_1_0.java:774)
        at com.sun.corba.ee.impl.encoding.CDROutputObject.write_value(CDROutputObject.java:681)
        at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl$14.write(DynamicMethodMarshallerImpl.java:394)
        at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl.writeResult(DynamicMethodMarshallerImpl.java:490)
        at com.sun.corba.ee.impl.presentation.rmi.ReflectiveTie._invoke(ReflectiveTie.java:180)
        at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatchToServant(CorbaServerRequestDispatcherImpl.java:682)
        at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(CorbaServerRequestDispatcherImpl.java:216)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(CorbaMessageMediatorImpl.java:1841)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:1695)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleInput(CorbaMessageMediatorImpl.java:1078)
        at com.sun.corba.ee.impl.protocol.giopmsgheaders.RequestMessage_1_2.callback(RequestMessage_1_2.java:221)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:797)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.dispatch(CorbaMessageMediatorImpl.java:561)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.doWork(CorbaMessageMediatorImpl.java:2558)
        at com.sun.corba.ee.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.performWork(ThreadPoolImpl.java:492)
        at com.sun.corba.ee.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.run(ThreadPoolImpl.java:528)

I think the problem is in marshalling of objects of Car class. How can resolve this problem with object marshalling?

Answer 1

The Car class must implement java.io.Serializable so that it can be serialized and transferred 'over the wire'. Reference: Java serialization

Also make sure all fields of the Car class are of serializable types. For example Car may have an private Engine engine field. Engine must be serializable as well. (or marked with transient if it is to be ignored during serialization)