Name: rm29839 Date: 12/08/97


I'm using jdk1.1.1 to run an rmi server
on my computer which is connected to the network
at the the University of Delaware through a
dial-up ppp acount. The jdk version I'm using on my
shell account is also 1.1.1. When I try to run a
rmi server from my computer using my dialin IP
as the server address, I get an error. Once I start
the client from my shell account, the name of my
computer appears on the client side and the client
reports that it is an unknown host. Just in case
this was related to the fact that my computer name
doesn't have a DNS entry (since it's a dialin, and
is assigned by the server), I changed the name of
my computer to the current IP of my dialin session.
It still reports the same error, but now with the IP
of the server. I tried running the 1.1.1 byte-codes
(I didn't recompile) on a 1.1 virtual machine and
it worked! I think this is a strange problem and
that it shouldn't require this workaround. It
would seem that something is different with the
rmiregistry with the 1.1 jdk in that it doesn't
try to return the machine name, or if it is, it
does it in a way that the client can find the server.
I don't see why people using rmi should have to
use the oldest version of the jdk for the server,
they should be able to at least use the same version,
but it would seem that doesn't work. It works GREAT
if I run the client and sever on the SAME machine,
but as soon as I split them up, it fails and I have to
use jdk1.1. It's a great feature (RMI), don't get me wrong,
but I thought you should be made aware of this problem,
it's very frustrating. I hope that there will be a
solution for it.

here's my code, it's very simple, I made it that
way just in case the code I originally found the
problem in was causing a problem due to file I/O,
which it wasn't. So I tried the simplest example
possible, still no luck.


package hello;

import java.rmi.*;
import java.rmi.server.*;
import java.net.*;

public class HelloImpl extends UnicastRemoteObject implements Hello {

   public HelloImpl() throws RemoteException {
      super();
   }

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

   public static void main(String args[]) {

      RMISecurityManager sm = new RMISecurityManager();
System.setSecurityManager(sm);

      try{
HelloImpl h = new HelloImpl();
Naming.rebind("rmi://" + args[0] + "/hello", h);
System.out.println("Hello server ready.");
      }
catch (RemoteException e) {
System.out.println("Exception in HelloImpl.main: " + e);
}

catch(MalformedURLException e) {
System.out.println("MalformedURLException in HelloImpl.main: " + e);
}
   }
}


package hello;
import java.rmi.*;

public class HelloClient {

   public static void main(String args[]) {

RMISecurityManager sm = new RMISecurityManager();
System.setSecurityManager(sm);

try{
Hello h = (Hello)Naming.lookup("rmi://" + args[0] + "/hello");
System.out.println("Reference to remote stub has been obtained."); //for debugging

String message = h.sayHello();
System.out.println("HelloClient: " + message);
}
catch (Exception e) {
System.out.println("Exception in main: " + e);
}
   }
}

package hello;

import java.rmi.*;

public interface Hello extends Remote {

   public String sayHello() throws java.rmi.RemoteException;

}


Here's the exact text produced by the client
when the error occurs, the server doesn't report
any error, it fact, when I set the LogStream
to report to System.out, it never even got
as far as leasing the object.

> java hello.HelloClient 128.175.98.92
Reference to remote stub has been obtained.
Exception in main: java.rmi.UnknownHostException: Unknown host: [zeppelin:1165];
 nested exception is:
        java.net.UnknownHostException: zeppelin
>
(Review ID: 21503)
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