Are RMI Registry and RMI Server have different port numbers?

Question

My impression about RMI is as if they are different servers. I write an Interface as:

package pack;
import java.rmi.*;

public interface AddI extends Remote
{
        public int add(int x, int y) throws Exception;
}

The class whose object to be served as:

package pack;
import java.rmi.server.*;
public class AddC extends UnicastRemoteObject implements AddI
{
        public AddC() throws Exception
        {
                super();
        }
        public int add(int x, int y)
        {
                int i = 2;
                while(i>0);
                return x+y;
        }
}

I want the add() method of above class to get stuck in while loop.

I write a Server program as:

package pack;
import java.rmi.*;
public class Server
{
        public static void main(String[] args) throws Exception
        {
                AddC obj = new AddC();
                Naming.rebind("rmi://10.100.11.238:1099/ADD", obj);
                System.out.println("Server Started");
        }
}

Then client program:

package pack;
import java.rmi.*;
public class Client
{
        public static void main(String[] args) throws Exception
        {
                AddI obj = (AddI)Naming.lookup("rmi://10.100.11.238:1099/ADD");
                int n = obj.add(5, 4);
                System.out.println(n);
        }
}

I started rmiregistry at port 1099 and run nmap command as:

$ nmap 127.0.0.1

Starting Nmap 7.01 ( https://nmap.org ) at 2016-11-24 15:14 IST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00011s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE
21/tcp   open  ftp
80/tcp   open  http
1099/tcp open  rmiregistry

I already have a web server running in my system. Then I run server program as:

$java pack.Server

Then after I run client in different machine as:

$java pack.Client

Since add() method has stuck in while loop so RMI server is not finished yet. In between if I run nmap again, it is not showing any extra open port.

Are both servers different or same?