NotSerializableException and Preferences

Question

Hi all,
I've met a weird problem. I have a RMI program, it works fine. But after I add some Preferences codes into the program, it breaks. The exception says that some Preferences are not serializable, but in fact, I don't send Preference as parameter or return value. Any hint? Thank you for your time.
the following is exception dump :
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
     java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: java.util.prefs.WindowsPreferences
     at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:164)
     at suncertify.dbserver.RemoteConnectionManager_Stub.connect(Unknown Source)
     at suncertify.client.FlightInfoClient.run(FlightInfoClient.java:142)
     at suncertify.client.FlightInfoClient.main(FlightInfoClient.java:55)
code of FlightInfoClient.java:142, this is RMI client
remoteSession = (IRemoteSession) connectionManager.connect();
code of connectionManager.connect(), this is RMI server
public IRemoteSession connect() throws RemoteException {
return new RemoteSession();
code of RemoteSession, this is RMI server
public class RemoteSession extends UnicastRemoteObject
implements IRemoteSession, Unreferenced {
private static RMIClientSocketFactory clientSocketFactory = new DataClientSocketFactory();
private IRemoteData dataService;
* remote session's logger
private final Logger logger = Logger.getLogger(getClass().getName());
public RemoteSession() throws RemoteException {
super(0, clientSocketFactory, RMISocketFactory.getDefaultSocketFactory());

Answer 1

i'm having a similar problem. I'm running a simple RMI program, but the object i'm trying to retrieve (fr.dyade.aaa.joram.TextMessage) is a proprietary one, that does not implement Serializable Interface. I think our problem is similar in a way, and we might want to find a way of MAKING OBJECTS SERIALIZABLE (or writable). Its not really an RMI problem, more one of changing an objects characteristics.
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: fr.dyade.aaa.joram.TextMessage
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: fr.dyade.aaa.joram.TextMessage
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:164)
at PL_ServerImpl_Stub.getMessageVector(PL_ServerImpl_Stub.java:51)
at PL_Client_screen.jButton2_actionPerformed(PL_Client_screen.java:211)