RMI connection refused

Question

Hello to all,
I have created and completed an RMI chat application and tested it on my localhost. It worked all right.
Now I want to make it live i.e. run it through internet.
Is it same as running on localhost only we have to change the IP address for locating registry.
I have done that and uploaded the server file on host, also I have the IP address of that host.
I have replaces localhost whit the give IP address but connection refused exception is thrown.
I have located the registry on the server through IP address then when I use
Registry reg=LocateRegistry("xx.xx.xx.xxx");
System.out.println("1");
chatAppIF chatStub=(chatAppIF)Naming.lookup("rmi://xx.xx.xx.xxx:xxxx/service");
System.out.println("2");
int i=chatStub.logMeIn(user,pass);
System.out.println("3");Output screen shows
1
2
Client exception: java.rmi.ConnectException: Connection refused to host: xx.xx.xx.xxx; nested exception is:
        java.net.ConnectException: Connection refused: connectWhile when i use
Registry reg=LocateRegistry("xx.xx.xx.xxx");
System.out.println("1");
chatAppIF stub=(chatAppIF)reg.lookup("service");
System.out.println("2");
int i=chatStub.logMeIn(user,pass);
System.out.println("3");it give output as
1
Client exception: java.rmi.ConnectException: Connection refused to host: xx.xx.xx.xxx; nested exception is:
        java.net.ConnectException: Connection refused: connectIs there is difference between naming.lookup() and reg.lookup() method?
I think Naming.lookup() finds the registry but cannot find the method logMeIn() while reg.lookup() has no success.
anyway why the connection is refused?

Answer 1

The argument to Naming.bind()/rebind()/unbind() and Naming.lookup() is a URI of the form rmi://hostname[:port]/path.
The argument to Registry.bind()/rebind()/unbind() and Registry.lookup() is just the path part.
The data returned by Naming.list() is an array of URIs.
The data returned by Registry.list() is an array of paths.
In other words Naming.list() returns items which can be used as arguments to Naming.lookup(), and Registry.list() returns items which can be used as arguments to Registry.lookup().
The reason is that when you construct a Registry, via LocateRegistry.getRegistry(), you supply the host and port at that point, so specifying it again in the bind/lookup string would be redundant. There's nothing stopping you doing that but the resulting name won't be compatible with what Naming.bind() would have done.