RMI Server problem, errors

[Siamak Saarmann]

Hello,

I am sorry to bring this subject again (lots of people have asked the same thing but I was not able to solve my problem through those threads).

I have this problem with Sun's example. (from API reference)

1- I have compiled java implementaion and interface files ( javac Hello.java HelloImpl.java )
2- I have run rmic ( rmic HelloImpl ) and I have my stub and skeleton class files
3- The directory which contains all these files is on my CLASSPATH.
4- I have granted all permissions in my .java.policy
5- I have all 4 files in my directory
6- I have run rmiregistry.exe and it run without any message

Yet I get below error.

I have the same problem with RMI example from the book "Java2 Enterprise Edition 1.4 Bible".

I really appereciate your help.

Regards,
Mac
ProgrammerNet.org

import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;
import java.rmi.server.UnicastRemoteObject;

public class HelloImpl extends UnicastRemoteObject implements Hello {

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

  public String sayHello() {
    return "Hello World!";
  }

  public static void main(String args[]) {
   //Create and install a security manager
   if (System.getSecurityManager() == null) {
    System.setSecurityManager(new RMISecurityManager());
   }

   try {
      HelloImpl obj = new HelloImpl();

      // Bind this object instance to the name "HelloServer"
      Naming.rebind("//sarmady2/HelloServer", obj);

      System.out.println("HelloServer bound in registry");
       } catch (Exception e) {
         System.out.println("HelloImpl err: " + e.getMessage());
         e.printStackTrace();
         }
       }
}

HelloImpl err: RemoteException occurred in server thread; nested exception is:
        java.rmi.UnmarshalException: error unmarshalling arguments; nested excep
tion is:
        java.lang.ClassNotFoundException: HelloImpl_Stub
java.rmi.ServerException: RemoteException occurred in server thread; nested exce
ption is:
        java.rmi.UnmarshalException: error unmarshalling arguments; nested excep
tion is:
        java.lang.ClassNotFoundException: HelloImpl_Stub
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:352
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:207)
        at sun.rmi.transport.Transport$1.run(Transport.java:148)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:4
60)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:701)
        at java.lang.Thread.run(Thread.java:534)
        at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Stream
RemoteCall.java:247)
        at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:
223)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:350)
        at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
        at java.rmi.Naming.rebind(Naming.java:160)
        at HelloImpl.main(HelloImpl.java:26)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested ex
ception is:
        java.lang.ClassNotFoundException: HelloImpl_Stub
        at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:342
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:207)
        at sun.rmi.transport.Transport$1.run(Transport.java:148)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:4
60)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:701)
        at java.lang.Thread.run(Thread.java:534)
Caused by: java.lang.ClassNotFoundException: HelloImpl_Stub
        at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:219)
        at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:430)
        at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:165)
        at java.rmi.server.RMIClassLoader$2.loadClass(RMIClassLoader.java:631)
        at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:257)

[Siamak Saarmann]

Hello again.

Sorry. I finally found the problem in SUN's RMI FAQ.

When I started the rmiregistry my codebase was not on my CLASSPATH (as I had created the directory and settings after running the rmiregistry).

By the way I am really really happy of finding this forum. Here seems to be Paradise of java programmers. (I hate SUN's forums as it is very slow and hard to navigate).

I really thank the owner's and people who have made here such a giant java community.

Regards,
Mac


Here is the FAQ:

6.2 If you encounter a problem running your RMI client
The second problem you could encounter is the receipt of a ClassNotFoundException when attempting to lookup a remote object in the registry. If you receive this exception in a stacktrace resulting from an attempt to run your RMI client code, then your problem is the CLASSPATH with which your RMI registry was started. See requirement C in section 6.0. Here is what the exception will look like:

java.rmi.UnmarshalException: Return value class not found; nested exception is:
java.lang.ClassNotFoundException: MyImpl_Stub
at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java:109
at java.rmi.Naming.lookup(Naming.java:60)
at RmiClient.main(MyClient.java:28)

[Sam Don]

Just wondering what IDE were you using ,, or is that done on UNIX , I am struggling getting my stub and skelton created using websphere.

[Aster Pan]

Well, I met the same problem too.

The message above has helped me with this.

If your OS is windows-based, when you run rmiregistry and your server, the enviornment variable CLASSPATH of both the two consoles must be set to refer your classpath.

I have forgot to set CLASSPATH to the console running rmiregistry before reading this message^^.