Java RMI Example, Reference=http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Java_remote_method_invocation.html

no.policy

grant {
    permission java.net.SocketPermission "127.0.0.1:*", "connect,resolve";
};

RmiClient.java

import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;
 
public class RmiClient { 
    // "obj" is the reference of the remote object
    RmiServerIntf obj = null; 
 
    public String getMessage() { 
        try { 
            obj = (RmiServerIntf)Naming.lookup("//localhost/RmiServer");
            return obj.getMessage(); 
        } catch (Exception e) { 
            System.err.println("RmiClient exception: " + e); 
            e.printStackTrace(); 
 
            return e.getMessage();
        } 
    } 
 
    public static void main(String args[]) {
        // Create and install a security manager
        if (System.getSecurityManager() == null) {
            System.setSecurityManager(new RMISecurityManager());
        }
 
        RmiClient cli = new RmiClient();
 
        System.out.println(cli.getMessage());
    }
}

RmiServer.java

import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.registry.*; 
 
public class RmiServer extends UnicastRemoteObject 
    implements RmiServerIntf {
    public static final String MESSAGE = "Hello world";
 
    public RmiServer() throws RemoteException {
    }
 
    public String getMessage() {
        return MESSAGE;
    }
 
 
    public static void main(String args[]) {
        System.out.println("RMI server started");
 
        // Create and install a security manager
        if (System.getSecurityManager() == null) {
            System.setSecurityManager(new RMISecurityManager());
            System.out.println("Security manager installed.");
        } else {
            System.out.println("Security manager already exists.");
        }
 
        try { //special exception handler for registry creation
            LocateRegistry.createRegistry(1099); 
            System.out.println("java RMI registry created.");
        } catch (RemoteException e) {
            //do nothing, error means registry already exists
            System.out.println("java RMI registry already exists.");
        }
 
        try {
            //Instantiate RmiServer
            RmiServer obj = new RmiServer();
 
            // Bind this object instance to the name "RmiServer"
            Naming.rebind("//localhost/RmiServer", obj);
 
            System.out.println("PeerServer bound in registry");
        } catch (Exception e) {
            System.err.println("RMI server exception:" + e);
            e.printStackTrace();
        }
    }
}

RmiServerIntf.java

import java.rmi.Remote;
import java.rmi.RemoteException;
 
public interface RmiServerIntf extends Remote {
    public String getMessage() throws RemoteException;
}

run.txt

javac RmiServer.java 
---> RmiServer.class
---> RmiServerIntf.class

rmic RmiServer
---> RmiServer_Stub.class

javac RmiClient.java
---> RmiClient.class

java -Djava.security.policy=server.policy RmiServer
java -Djava.security.policy=no.policy RmiClient

server.policy

grant {
    permission java.net.SocketPermission "127.0.0.1:*", "connect,resolve";
    permission java.net.SocketPermission "127.0.0.1:*", "accept";
};