A rmi problem about exporting a remote object

Question

here is the code:
public interface Hello extends Remote {
String sayHello() throws RemoteException;
public class HelloImpl extends UnicastRemoteObject
implements Hello {
public HelloImpl() throws RemoteException {
super();
public String sayHello() {
return "Hello World!";
public static void main(String args[]) {
if (System.getSecurityManager() == null) {
     System.setSecurityManager(new RMISecurityManager());
try{
     HelloImpl obj = new HelloImpl();
     Naming.rebind("//192.168.10.2:2001/HelloServer", obj);
     System.out.println("HelloServer bound in registry");
}catch (Exception e) {
     System.out.println("HelloImpl err: " + e.getMessage());
e.printStackTrace();
public class HelloClient{
public static void main(String[] args){
Hello obj = null;
String message="nobody say hello to me";
if (System.getSecurityManager() == null) {
     System.setSecurityManager(new RMISecurityManager());
try {
     obj = (Hello)Naming.lookup("//192.168.10.2:2001/HelloServer");
     message = obj.sayHello();
}catch (Exception e) {
     System.out.println("exception: "+e.getMessage());
     e.printStackTrace();
System.out.println(message);
where 192.168.10.2 is the ip address of my computer.
i'm using an mini-http server provided by sun,that is,ClassFileServer
here is my command lines:
java examples.classServer.ClassFileServer 2003 d:\java\rmi
start rmiregistry 2001
java -Djava.rmi.server.codebase=http://192.168.10.2:2001/
-Djava.security.policy=server.policy HelloImpl
then encountered the exception.
can someone tell me how can i export the HelloImpl and
make it can be invoked by client.
thanks a lot!

Answer 1

thank you for your reply,i tried it again like below:
java examples.classServer.ClassFileServer 2001 d:\java\rmi
start rmiregistry
java -Djava.rmi.server.codebase=http://192.168.10.2:2001/
-Djava.security.policy=server.policy HelloImpl
java HelloClient
but could not work,the exception raised at the client point is like that:
java.rmi.Naming.lookup(unknown source)....
i want to know how could the client know how to contact with
rmiregistry,where the client trying to lookup(//192.168.10.2:2001/HelloServer)
while rmiregistry running on the port 1099.
thank you!