RMI Applet error

Question

I'm programming a RMI based messenger system. I tested the server and a java console client... all worked very well!
After that, I programmed a very simple test applet (source below).
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.rmi.*;
import java.rmi.server.*;
public class MessageApplet extends Applet {
     private MessageDaemon messaged;
     public MessageApplet() {}
     public void init() {
          try {
               // connect RMI Server
               messaged = (MessageDaemon)Naming.lookup("rmi://myhost.net/messaged");
// RMI test
               System.out.println(messaged.whois("username").getName());
          catch (Exception e) {
               e.printStackTrace();
I start the applet under Windows 98 (JDK 1.3.1) with the following command:
appletviewer MessageApplet.html
and all I get is the following exception:
java.security.AccessControlException: access denied (java.net.SocketPermission myhost.net resolve)
at java.security.AccessControlContext.checkPermission(Compiled Code)
at java.security.AccessController.checkPermission(Compiled Code)
at java.lang.SecurityManager.checkPermission(Compiled Code)
at java.lang.SecurityManager.checkConnect(SecurityManager.java:1004)
at java.net.InetAddress.getAllByName0(Compiled Code)
at java.net.InetAddress.getAllByName0(InetAddress.java:544)
at java.net.InetAddress.getByName(Compiled Code)
at java.net.Socket.<init>(Socket.java:98)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirect SocketFactory.java:29)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Compiled Code)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:462)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:194)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Compiled Code)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:306)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at java.rmi.Naming.lookup(Naming.java:89)
at MessageApplet.init(MessageApplet.java:27)
at sun.applet.AppletPanel.run(Compiled Code)
at java.lang.Thread.run(Thread.java:479)
If I run the same applet unter MRJ (Mac OS Runtime for Java, JDK 1.1.8, Apple Applet Runner) on my Mac, I get another exception:
java.rmi.UnmarshalException: Return value class not found; nested exception is: java.lang.ClassNotFoundException: MessageDaemonImpl_Stub
at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java)
at java.rmi.Naming.lookup(Naming.java)
at MessageApplet.init(MessageApplet.java:27)
at com.apple.mrj.JManager.JMAppletViewer_OLD.doAppletInit(JMAppletViewerOld.java)
at com.apple.mrj.JManager.JMAppletViewer_OLD.setState(JMAppletViewerOld.java)
at com.apple.mrj.JManager.JMViewerEvent.post(JMAppletViewerOld.java)
at com.apple.mrj.JManager.AVDispatcherThread.run(JMAppletViewerOld.java)
What could be the problem? Do I have to add some permissions? The client could load the MessageDaemonImpl_Stub class without any problems, so there is surely no problem with the server/rmiregistry.
Thank you very much.
Best Regards,
Adrian R.

Answer 1

some additional information:
I started the applet with appletviewer (1.3.1) under Windows...
appletviewer http://192.168.0.1/msg/MessageApplet.html
(no problems)
appletviewer http://myhost.net/msg/MessageApplet.html
(security exception allthough myhost.net is the same host as 192.168.0.1!)
The server ist running on a linux system with 2 network interfaces: LAN: 192.168.0.1 and WAN: (DHCP, dynamically linked to a DNS). I'm testing the applet from a host in the LAN and only the url http://192.168.0.1/msg/MessageApplet.html did work.
I also tested the applet with MS IE 6 and all I got is the following exception:
java.lang.ClassNotFoundException: java.rmi.Naming
on my Mac I tested the applet in MS IE 5 and it worked with the URL: http://192.168.0.1/msg/MessageApplet.html but http://myhost.net/msg/MessageApplet.html didn't work.
What about IE 6? Is it possible that IE doesn't support RMI?!?! But what to do? And how can I solve the problem regarding "IP vs. DNS"?
Best Regards
Adrian R.