ServerSocket: listening on a port in 2 seconds

import java.net.InetAddress;
import java.net.ServerSocket;


public class SS {
 public static void main(String[] args) throws Throwable {
  InetAddress inet = InetAddress.getByName("192.168.6.110");
  ServerSocket ss = new ServerSocket(7001, 100, inet);
  ss.accept();
 }
}

After that, if you run
ss -ln | grep 7001
you should see your fish swimming, and be able to telnet into it.
(ah of course: javac SS.java, java SS) To check if something is listening on an IP/port:

import java.net.InetAddress;
import java.net.Socket;


public class CS {
 public static void main(String[] args) throws Throwable {
  InetAddress inet = InetAddress.getByName("192.168.6.110");
  Socket so = new Socket(inet, 7001);
  so.getInputStream();
 }
}