RMI Client Code Issue

Question

Hello,
Here is my client side RMI program:
import java.rmi.*;
public class MyRemoteClient {
public static void main(String args[]) {
MyRemoteClient mm = new MyRemoteClient();
mm.go();
public void go(){
try{
MyRemote service2 = (MyRemote) Naming.lookup("rmi://xxx.xxx.xx.xx/Hello");
String s = service2.sayHello();
System.out.println(s);
} catch(Exception ex){ex.printStackTrace();}
}Having started RMI Registry and Service Implementor code on the server, if I try to run the above code on the client it fire the following error:
java.rmi.ConnectException: Connection refused to host: 127.0.1.1; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at MyRemoteImpl_Stub.sayHello(Unknown Source)
at MyRemoteClient.go(MyRemoteClient.java:11)
at MyRemoteClient.main(MyRemoteClient.java:6)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
... 7 more
I am wondering as to why is it trying to connect to a local host 127.0.1.1 instead of the IP Address specified at by"xxx.xx.xx.xx" in the program?
I have the stub class and the service interface classes on my client-side.
Thanks.

Answer 1

I am wondering as to why is it trying to connect to a
local host 127.0.1.1 instead of the IP Address
specified at by"xxx.xx.xx.xx" in the program?Because that only specifies where the lookup should be done, i.e. where the Registry is. This lookup() returns a stub to your remote object which has its own IP address and port embedded into it, and that's where 127.0.0.1 is coming from - you're not doing Registry.lookup at this point, you're calling your remote method.
This indicates a DNS or /etc/hosts misconfiguration - your primary IP address is coming up as 127.0.0.1 instead of whatever your public IP address is. Famous Linux issue. You should really fix it in your DNS or /etc/hosts, but you can work around it by setting -Djava.rmi.server.hostname=<public IP address> at the server JVM.