Java RMI Error

mark renton

Hey peoples - my java rmi knowledge is fairly basic- i have setup server and client for the obligitory java chat program

I keep gettin error below and cannot for the life of me get around it (have been staring at screen for too long) - eclipse is happy with all my code

can anyone tell me where im going wrong?


Error

[U][SIZE=2][COLOR=#000080][SIZE=2][COLOR=#000080]java.lang.ClassCastException[/COLOR][/SIZE][/COLOR][/SIZE][/U][SIZE=2][COLOR=#ff0000][SIZE=2][COLOR=#ff0000]: $Proxy0 cannot be cast to ChatServer[/COLOR][/SIZE]
[/COLOR][/SIZE]

Server Code

 
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.util.LinkedList;
 
 
public class DITChatServer extends UnicastRemoteObject {
 
 /**
  * 
  */
 private static final long serialVersionUID = 1L;
 
 // linked list
 public LinkedList<ChatClient> logins;
 // constructor - creates 
 public DITChatServer() throws RemoteException {
  logins = new LinkedList<ChatClient>();
 
 
 }
 
 //method to record new client (add client to linked list)
 public void newClient(ChatClient name) throws RemoteException {
  logins.add(name);
 }
 
 //method to send message (uses receive method for clients)
 public void sendMessage(String text) throws RemoteException {
  for (int i = 0; i < logins.size(); i++) {
   logins.get(i).getMessage(text);
  }
 }
 
 // in main bind service
 public static void main(String[] args) {
  try {
   Naming.rebind("rmi://localhost/chat", new DITChatServer());
  } catch (Exception e) {
   System.err.println(e);
   System.err.println("Error Binding");
  }
 
  System.err.println("Accepting Connections");
 
 }
 
}
 

Client Code

 
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.util.Scanner;
 
public class DITChatClient implements ChatClient, Runnable{
 
 //create instance of chat server and call server
 public ChatServer server;
 
 
 //constructor for DIT Chat Client
 public DITChatClient(ChatServer cs) throws RemoteException {
 
  server = cs;
  server.newClient(this);
 
 }
 
 public void getMessage(String message) throws RemoteException{
  System.out.println("Message :" + message);
 }
 
 public synchronized void run() {
  Scanner in = new Scanner(System.in);
  String text;
  while (true) {
   try {
    text = in.nextLine();
    server.sendMessage(text);
   } catch (Exception e) {
    System.err.println(e);
   }
  }
 }
 
 public static void main(String[] args) {
 
  try {
   ChatServer cs = (ChatServer) Naming.lookup("rmi://localhost/chat");
   new Thread(new DITChatClient(cs)).start();
  } catch (Exception e) {
   System.err.println(e);
  }
 }
 
 
 
 
 }
 

Server Interface

 
import java.rmi.Remote;
import java.rmi.RemoteException;
 
public interface ChatServer extends Remote{
 void newClient(ChatClient name) throws RemoteException;
 void sendMessage(String text) throws RemoteException;
 }
 

Client Interface

 
 
[B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]import[/COLOR][/SIZE][/COLOR][/SIZE][/B][SIZE=2][COLOR=#7f0055]
[LEFT][/COLOR][/SIZE][SIZE=2]java.rmi.*;[/SIZE][/LEFT]
 

[LEFT][B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]public[/COLOR][/SIZE][/COLOR][/SIZE][/B][/LEFT]
[SIZE=2][COLOR=#7f0055]
 
[LEFT][/COLOR][/SIZE][B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]interface[/COLOR][/SIZE][/COLOR][/SIZE][/B][SIZE=2] ChatClient [/SIZE][B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]extends[/COLOR][/SIZE][/COLOR][/SIZE][/B][SIZE=2] [U]Remote[/U]{[/SIZE]

[B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]void[/COLOR][/SIZE][/COLOR][/SIZE][/B][/LEFT]
[SIZE=2][COLOR=#7f0055]
 
[LEFT][/COLOR][/SIZE][SIZE=2]getMessage(String message) [/SIZE][B][SIZE=2][COLOR=#7f0055][SIZE=2][COLOR=#7f0055]throws[/COLOR][/SIZE][/COLOR][/SIZE][/B][SIZE=2] RemoteException;[/SIZE]
[SIZE=2]}[/SIZE][/LEFT]
 

mark renton

Another day another dawn - i missed chat server implementation implementing chatserver interface

also extending UnicastRemoteObject on client implementation