RMI - ClassCastException - Proxy cannot be cast

[driiper]

Hello, i'm currently switching to RMI for networking in my application, i have followed some tutorials, read some on Oracles RMI pages and i belive i understand the concept behind it.

I found a example on the net and its working with transmitting Strings. however when i try to send my own object it get the error:

HelloClient exception: java.lang.ClassCastException: sun.proxy.$Proxy0 cannot be cast to saqib.rasul.server.Fag
java.lang.ClassCastException: sun.proxy.$Proxy0 cannot be cast to saqib.rasul.server.Fag
	at sun.proxy.$Proxy0.returnFag(Unknown Source)
	at saqib.rasul.server.dd.main(dd.java:19)

Googling for this error tells me from what i can understand that i have not implemented the interface in my class. But i have (Fag implements FagInterface).

So yeh, i have no idea why i get this error, and what it means.

Client.java

package saqib.rasul.server;

import java.rmi.Naming;



public class Client {
	  /**
	   * Client program for the "Hello, world!" example.
	   * @param argv The command line arguments which are ignored.
	   */
	  public static void main (String[] argv) {
	    try {
	   //   HelloInterface hello = (HelloInterface) Naming.lookup ("//localhost/Hello");
	      FagInterface fag = (FagInterface) Naming.lookup("//localhost/Fag");

	      
	     // System.out.println (hello.say());
	      System.out.println(fag.returnFag());
	    } catch (Exception e) {
	      System.out.println ("HelloClient exception: " + e);
	      e.printStackTrace();
	    }
	  }
}

Breaks on: System.out.println(fag.returnFag());

Server.java

package saqib.rasul.server;

import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;

public class Server {
	/**
	 * Server program for the "Hello, world!" example.
	 * @param argv The command line arguments which are ignored.
	 */
	public static void main (String[] argv) {
		try {
			java.rmi.registry.LocateRegistry.createRegistry(1099);
			System.out.println("RMI registry ready.");
			//Naming.rebind ("Hello", new Hello ("Hello, world!"));
           
			String name = "Fag";
            FagInterface engine = new Fag("Universi");
            FagInterface stub =
                (FagInterface) UnicastRemoteObject.exportObject(engine, 0);
            Registry registry = LocateRegistry.getRegistry();
            registry.rebind(name, stub);
			
			System.out.println ("Hello Server is ready.");
		} catch (Exception e) {
			System.out.println ("Hello Server failed: " + e);
		}
	}
}

FagInterface.java

package saqib.rasul.server;

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface FagInterface extends Remote{

	public Fag returnFag() throws RemoteException;
	
	
}

Fag.java

package saqib.rasul.server;

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.util.ArrayList;

/**
 * 
 * @author Per-Arne
 * @description Simple class which contains all subjects (fag) in a single course (kurs). The way this class works is that it takes a ArrayList with subject for a whole week. Then this week is added to another ArrayList which then is the grand total of subjects.
 */
public class Fag implements FagInterface{
	private static final long serialVersionUID = 1L;
	public String fagName;
	public ArrayList<ArrayList<FagTime>> weeks;
	private Fag fag;

	public Fag(String fagName) throws RemoteException{
		this.fag = this;
	}

	/**
	 * @param week - Contains a whole week with subjectData, this is added to this course.
	 */
	public void addWeek(ArrayList<FagTime> week) throws RemoteException{
		weeks.add(week);
	}

	public Fag returnFag() throws RemoteException {
		return fag;
	}		
}

Thanks
Driiper

[driiper]

Figured it out...

I had to use the same package name (Which makes sense)