I hava a question about RMI,please help me!

Question

Ladys and Gentleman,I hava a question about RMI.I wirte four little programs in java that is about RMI on my PC.
import java.rmi.*;
public interface AddServerIntf extends Remote{
double add(double d1,double d2) throws RemoteException;
import java.rmi.*;
import java.rmi.server.*;
public class AddServerImpl extends UnicastRemoteObject implements AddServerIntf{
public AddServerImpl() throws RemoteException{
public double add(double d1,double d2)throws RemoteException{
return d1+d2;
import java.net.*;
import java.rmi.*;
public class AddServer{
public static void main(String args[]){
try{
AddServerImpl addServerImpl=new AddServerImpl();
Naming.rebind("AddServer",addServerImpl);
}catch(Exception e){
e.printStackTrace();
import java.rmi.*;
public class AddClient
     public static void main(String args[]){
     try{
     String addServerURL="rmi://"+args[0]+"/AddServer";
     AddServerIntf addServerIntf=(AddServerIntf) Naming.lookup(addServerURL);
     System.out.println("The first number is: "+args[1]);
     double d1=Double.valueOf(args[1]).doubleValue();
     System.out.println("The second number is: "+args[2]);
     double d2=Double.valueOf(args[2]).doubleValue();
     System.out.print("The sum is: "+addServerIntf.add(d1,d2));
     }catch(Exception e){
     System.out.println("Exception: "+e);
And I compiled these files,so I got 4 class files(AddServer.class,AddServerIntf.class,AddServerImpl.class,AddServerClient.class).Then I use "rmic AddServerImpl" got another two files(AddServerImpl_Skel.class and AddServerImpl_Stub.class).Then I input command:rmiregistry,in another window,I input command:java AddServer,I got some exceptions,I was confused by these exceptions.The exception is:
D:\MyJava\rmi_3>java AddServer
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: AddServerImpl_Stub
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: AddServerImpl_Stub
java.lang.ClassNotFoundException: AddServerImpl_Stub
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at java.rmi.Naming.rebind(Unknown Source)
at AddServer.main(AddServer.java:8)
But some times this exception will not appeared.Who can give me answer or suggestion,thanks a lot.
By the way,when I run shutdown.bat in tomcat_root\bin,I can get some exceptions:
C:\Tomcat\bin>shutdown
Using CATALINA_BASE: ..
Using CATALINA_HOME: ..
Using CATALINA_TMPDIR: ..\temp
Using JAVA_HOME: C:\JDK
Catalina.stop: java.net.ConnectException: Connection refused: connect
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:350)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:137)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:124)
at java.net.Socket.<init>(Socket.java:268)
at java.net.Socket.<init>(Socket.java:95)
at org.apache.catalina.startup.Catalina.stop(Catalina.java:579)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:402)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
at java.lang.reflect.Method.invoke(Native Method)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)
I use Windows server 2000+JDK 1.3.1_04+tomcat 4.1.7

Answer 1

Maybe I am off base here but it seems to me the problem is the way in which you bind your server. The server must be bound to the same address and you are looking up from, i.e. "rmi://" host "/AddServer"
so
Naming.rebind("AddServer",addServerImpl);should be
Naming.rebind("rmi://127.0.0.1/AddServer", addServerImpl);to match
String addServerURL="rmi://"+args[0]+"/AddServer";
AddServerIntf addServerIntf=(AddServerIntf)
Naming.lookup(addServerURL);Hopefully this will solve your problem, if not it is a problem with your classpath. An easy way to make sure it can see your files is to set the java.rmi.server.codebase to point to where your classes are, e.g.
java -Djava.rmi.server.codebase=file:"c:\\cygwin\\home\\tweak\\keck_folder\\cmsi401\\RMIGalaxySleuth\\classes\\" AddServer
I had to set the codebas for my rmi stuff to work no matter how much I messed with the classpath.
Hope this helps,
Will