Name: rm29839 Date: 11/05/97


We try to do rmi between different computers.
The App works in the following configs:
   - local in a WinNT(Client, Server)
   - local in a Win95(Client, Server)
   - remote WinNT(Client) WinNT(Server)
The App fails
   - remote WinNT (Client) Win95(Server) (seems not to receive a connection)
   - remote Win95(Client) WinNT(Server) (establishes connection and fails for callback to client object)
   - remote Win95(Client) Win95(Server) (not establishing connection)

The App is derived from the docs/rmi/examples/hello-Example
and does a callback to the client.

Code is here:
File Hello.java -------------------------------------------------------------
package examples.hello;

public interface Hello extends java.rmi.Remote {
    String sayHello(Holle obj) throws java.rmi.RemoteException;
    String sayHello(Testobject t) throws java.rmi.RemoteException;
    String sayHello( ) throws java.rmi.RemoteException;
}


File Holle.java -------------------------------------------------------------
// The callback-interface

package examples.hello;

public interface Holle extends java.rmi.Remote {
    String sayHolle() throws java.rmi.RemoteException;
}

File HelloImpl.java ----------------------------------------------------------
package examples.hello;


import java.rmi.*;
import java.rmi.server.*;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.registry.LocateRegistry;

public class HelloImpl extends UnicastRemoteObject implements Hello
{
    private String name;

    private String getClient()
    {
       String s = "<unbekannt>";
       try
       {
          s = getClientHost();
       }
       catch ( ServerNotActiveException e )
       {
          System.out.println("Server: " + e);
       }
       return s;
    }

    public HelloImpl(String s) throws java.rmi.RemoteException
    {
      super();
      name = s;
    }

    static int cnt = 0;
    public String sayHello(Testobject t) throws RemoteException
    {
      System.out.println( "Server: " + "Anfrage erhalten von " + getClient() + " (mit Testobject)");
      System.out.println( "Server: Testobject " + t.incName());
      cnt ++;
      return "Server says: Hello World-" + cnt + ":" + t.incName();
    }
    public String sayHello(Holle obj) throws RemoteException
    {
      System.out.println( "Server: " + "Anfrage erhalten von " + getClient() + " (mit obj)");
      System.out.println( "Server: " + obj );
      System.out.println( "Server: " + obj.sayHolle());
      cnt ++;
      return "Server says: Hello World (" + cnt + ", mit obj)";
    }
    public String sayHello() throws RemoteException
    {
      System.out.println( "Server: " + "Anfrage erhalten von " + getClient() + " (ohne Parameter)");
      cnt ++;
      return "Server says: Hello World (" + cnt + ", ohne Parameter)";
    }

    public static void main(String args[])
    {
      System.out.println("Server: create and install the security manager");
      System.setSecurityManager(new RMISecurityManager());

      try
      {
         System.out.println("Server: creating registry");
         LocateRegistry.createRegistry(2112);
         String my_name = "//:2112/HelloServer";
         System.out.println("Server: creating new Server '" + my_name + "'" );
         HelloImpl obj = new HelloImpl(my_name);
         Naming.rebind( my_name, obj );
         System.out.println( "Server created and bound in the registry to the name '" + my_name + "'");
         System.out.println( "Server: " + obj );
      }
      catch (Exception e)
      {
         System.out.println( "Server: " + "HelloImpl.main.exception:");
         e.printStackTrace();
      }
   }
}
File HelloClient.java --------------------------------------------------------------------------
package examples.hello;

import java.io.*;
import java.rmi.*;
import java.rmi.server.*;
import java.rmi.server.UnicastRemoteObject;
import java.net.InetAddress;

public class HelloClient extends UnicastRemoteObject implements Holle, Serializable
{
   private String addr, name;

   public HelloClient(String s, String a) throws java.rmi.RemoteException
   {
      super();
      name = s;

      addr = ("//" + a + ":2112/HelloServer");
// System.setSecurityManager(new RMISecurityManager());

      try
      {
         System.out.println("Local Host: "+ InetAddress.getLocalHost());
         Hello obj = (Hello) Naming.lookup( addr );

         System.out.println("Client: Server Objekt erzeugt (" + addr + "): " + obj);

         message = obj.sayHello( ); System.out.println("message="+message+" (ohne Parameter)");
         message = obj.sayHello( new Testobject("eins") ); System.out.println("message="+message+" (mit obj)");
         message = obj.sayHello( (Holle)this ); System.out.println("message="+message+" (mit obj)");

         Testobject t = new Testobject("zwei");
         for (int i = 0; i < 3; i ++ )
            System.out.println(i+". message="+obj.sayHello( t ));
      }
      catch (Exception e)
      {
         System.out.println("HelloClient.exception:");
         e.printStackTrace();
      }
   }

   String message = "";

   static public void main ( String argv[] )
   {
      String addr = "hepp-nt";

      if (argv.length > 0) addr = argv[ 0 ];

      System.out .println("Client: Adresse " + addr );

      try
      {
         HelloClient x = new HelloClient ("HelloClient", addr );

         System.out.println( "Client: " + x );
      }
      catch (Exception e)
      {
         System.out.println( "Client: " + "HelloClient.main.exception:");
         e.printStackTrace();
      }
      System.exit ( 0 );
   }

   static int cnt = 0;
   public String sayHolle() throws RemoteException
   {
      System.out.println( "Client: " + "Anfrage von Server erhalten");
      cnt ++;
      return "Antwort von Client: " +cnt;
   }
}

File Testobject.java ------------------------------------------------------

package examples.hello;

import java.io.*;

public class Testobject implements Serializable
{
   String name;
   static int cnt;
   public Testobject( String n )
   {
      name = n;
      cnt = 0;
   }
   public String incName()
   {
      return name + "_" + (cnt++);
   }
   public String toString()
   {
      return "Testobject[name=" + name + ",cnt="+ cnt + "]";
   }
}

Files end here ------------------------------------------------


Error message from WinNT(Client) to Win95(Server)

L:\RMI\EXAMPLES\HELLO>java examples.hello.HelloClient 138.200.187.62
Client: Adresse 138.200.187.62
Local Host: hepp-nt/138.200.187.79
Client: Server Objekt erzeugt (//138.200.187.62:2112/HelloServer): examples.hello.HelloImpl_Stub[RemoteStub [ref: [endpoint:[
ALG.aat-f.aeg-f.de:1173](remote),objID:[1cc776:cc27eef464:-8000, 0]]]]
HelloClient.exception:
java.rmi.UnknownHostException: Unknown host: [ALG.aat-f.aeg-f.de:1173]; nested exception is:
        java.net.UnknownHostException: ALG.aat-f.aeg-f.de
        at sun.rmi.transport.tcp.TCPChannel.openSocket(TCPChannel.java:238)
        at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:125)
        at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:73)
        at examples.hello.HelloImpl_Stub.sayHello(HelloImpl_Stub.java:31)
        at examples.hello.HelloClient.<init>(HelloClient.java:56)
        at examples.hello.HelloClient.main(HelloClient.java:83)
Client: examples.hello.HelloClient[RemoteStub [ref: [endpoint:[hepp-nt:1597](local),objID:[0]]]]


Error message from Win95(Client) to WinNT(Server)

C:\TMP\rmi\examples\hello>java -Djava.rmi.server.hostname=ALG.aat-f.aeg-f.de examples.hello.HelloClient
Client: Adresse hepp-nt
Local Host: ALG.aat-f.aeg-f.de/138.200.187.62
Client: Server Objekt erzeugt (//hepp-nt:2112/HelloServer): examples.hello.HelloImpl_Stub[RemoteStub [ref: [endpoint:[hepp-nt:1577](remote),objID:[1ea785:cc27a7b7ee:-8000, 0]]]]
message=Server says: Hello World (1, ohne Parameter) (ohne Parameter)
message=Server says: Hello World-2:eins_1 (mit obj)
HelloClient.exception:
java.rmi.ServerException: Server RemoteException; nested exception is:
        java.rmi.UnknownHostException: Unknown host: [ALG.aat-f.aeg-f.de:1112];
nested exception is:
        java.net.UnknownHostException: ALG.aat-f.aeg-f.de
Client: examples.hello.HelloClient[RemoteStub [ref: [endpoint:[ALG.aat-f.aeg-f.de:1112](local),objID:[0]]]]
(Review ID: 18737)
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