RMI no such object exception

Question

I was trying to run the Hello World RMI example from the Oracle page, but I keep getting errors.

the error I keep getting is

Server exception: java.rmi.NoSuchObjectException: no such object in table java.rmi.NoSuchObjectException: no such object in table at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:275) at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:252) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:378) at sun.rmi.registry.RegistryImpl_Stub.bind(Unknown Source) at example.hello.Server.main(Server.java:26)

Here is the code as taken directly from the site that I used:

The Hello Interface:

package example.hello;

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

public interface Hello extends Remote {
    String sayHello() throws RemoteException;
}

This is what my server class:

package example.hello;

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

public class Server implements Hello {

    public Server() {}

    public String sayHello() {
        return "Hello, world!";
    }

    public static void main(String args[]) {

    try {
        Server obj = new Server();
        Hello stub = (Hello) UnicastRemoteObject.exportObject(obj,0);

        // Bind the remote object's stub in the registry
        Registry registry = LocateRegistry.getRegistry("localhost");
        registry.bind("Hello", stub);

        System.err.println("Server ready");
        } catch (Exception e) {
            System.err.println("Server exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

Client code:

package example.hello;

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

public class Client {

    private Client() {}

    public static void main(String[] args) {

        String host = "localhost";
        try {
            Registry registry = LocateRegistry.getRegistry(host);
            Hello stub = (Hello) registry.lookup("Hello");
            String response = stub.sayHello();
            System.out.println("response: " + response);
        } catch (Exception e) {
            System.err.println("Client exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

Any feedback is greatly appreciated!

Answer 1

The Registry isn't running. Either start the rmiregistry tool, or change getRegistry() to createRegistry().

It's curious, as some JVM must have been listening on port 1099, but not with a Registry running in it. Normally no Registry causes a java.rmi.ConnectException.

Answer 2

I think your interface method should have public modifier