Java.rmi.MarshalException: error marshalling arguments

Question

I've two class Client and Main. Eventnotify is implemented in class Client using RMI techniques. Here is sample
public interface EventNotify extends Remote {
void SendNotification (String str) throws RemoteException;
public class Client implements EventNotify {
     //implementation of EventNotify
     public void SendNotification(String str) {
     System.out.println("from srver: ..." +str);
class Main {
public static void main(String[] args) {
Client clnt = new Client();
int val = stub.register_client(host, clnt); //THE ERROR IS HERE
The idea is to pass remote objects from client to a server. I've a server program running continously, but the problem is on passing objects of type Client. I'm facing marshaling problem.
AND THE ERROR IS
Client exception: java.rmi.MarshalException: error marshalling arguments; nested exception is:
     java.io.NotSerializableException: Client
java.rmi.MarshalException: error marshalling arguments; nested exception is:
     java.io.NotSerializableException: Client
     at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:156)
     at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:195)
     at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:149)
     at $Proxy0.register_client(Unknown Source)
     at Main.main(Client.java:74)
Thanks for helping.
Caused by: java.io.NotSerializableException: Client
     at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1173)
     at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:343)
     at sun.rmi.server.UnicastRef.marshalValue(UnicastRef.java:292)
     at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:151)

Answer 1

Probably I have a similar problem while calling remote object's method with parameter looks like that :
public class ParamClass extends AbstractParamClass implements Runnable,
        java.io.Serializable {
    private NodeList field1; // part of crimson's tree
    private NamedNodeMap field2 = null;// part of crimson's tree
public class RmiRemote extends AbstractRemote  { // Remote Object Class
@Override
public  Object remoteMethod1() throws RemoteException{
ParamClass param = new  ParamClass("build with crimson");
CustomInterface stub = (CustomInterface) registry.lookup(name);
stub.callRemoteMethod(param); // exception here
java.rmi.MarshalException: error marshalling arguments; nested exception is:
        java.io.NotSerializableException: org.apache.crimson.tree.AttributeSet
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:138)
        at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:178)when I build param object with xerces - no exception occurs . Other methods of remote object doing well. Remote object extends AbstractRemote superclass derived from UnicastRemoteObject. How can I avoid this problem and call method with crimson's tree fields parameter?
Thank you.