RMI- Problem with Serialization

[Saskia Schreiber]

Hi there,
I'm just testing some RMI-programms. I wrote an ServerImpl which got the method getJFrame() (it returns an JFrame) I've got the Interface which is extended from the RemoteInterface but when I want to start the Server it always brings me these errors:
java.rmi.MarshalException: error marshalling arguments; nested exception is:
java.io.NotSerializableException: de.xx.test.ServerImpl
java.io.NotSerializableException: de.xx.test.ServerImpl
at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366)
error marshalling arguments; nested exception is:
java.io.NotSerializableException: de.xx.test.ServerImpl
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at java.rmi.Naming.rebind(Naming.java:160)
at de.xx.test.ServerImpl.main(ServerImpl.java:31)
and here is my ServerImpl:
public class ServerImpl implements Saskia {
public ServerImpl() {
}
public JFrame getJFrame() throws RemoteException {
JFrame myFrame = new JFrame("Saskia's Test");
myFrame.setBackground(Color.blue);
myFrame.setBounds(100,100,100,100);
return myFrame;
}
public static void main(String[] args){
try {
ServerImpl si= new ServerImpl();
Naming.rebind("rmi://dpc04:7011/Server",(Remote)si);
}
catch (Exception ex) {
ex.printStackTrace();
System.out.println(ex.getLocalizedMessage());
}
}
}

[Peter den Haan]

JFrame is not serializable. A frame represents an OS resource and cannot be sent over the network. In general, things like GUI widgets, database connections and the like cannot be serialized and so cannot be passed into or returned from an RMI method.
- Peter

[Saskia Schreiber]

I implemented the interface Serializable to my Server-programm and now it's working fine (after I also added a RMISecurityManager to my program). I got a beautiful JFrame on the client although most RMI-books say that JFrame is not transportable over network... :-)

[Marco Barenkamp]

Hi,
remember that the client only got a copy of the original frame
created on the server and not the object itself.
Implementing Serializable in RMI means 'passByValue'
------------------
Marco Barenkamp
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