Testing Listening Port

PipeTest.java

package net.eckenfels.test.javasystemtest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.channels.Pipe;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/**
 * Opens a number of Pipes and waits for you to look up the used ports.
 * Enter one used port at a time, the program will tell you if it can bind.
 * Press enter to terminate.
 */
public class PipeTest
{
    static ExecutorService e = Executors.newFixedThreadPool(10);

    public static void main(String[] args) throws IOException
    {
        Pipe[] pipes = new Pipe[5];
        for(int i = 0;i < pipes.length; i++) {
            pipes[i] = Pipe.open();
        }
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        do {
            String l = br.readLine();
            int p = Integer.parseInt(l);
            ServerSocket s = null;
            try {
                if (s != null) s.close();
                s = new ServerSocket();
                s.setReuseAddress(true); // same problem with and without
                s.bind(new InetSocketAddress(/*"127.0.0.1", */p)); // works with 127.0.0.1
                accept(s);
            } catch (Exception ex) {
                System.out.println("Failed " + p + ": " +ex );
            }
        } while(true);
    }

    private static void accept(final ServerSocket s) throws InterruptedException, ExecutionException, TimeoutException, IOException
    {
        Future< ? > r = e.submit(() -> {
            System.out.print("accepting ... " + s);
            try
            {
                s.accept();
            } catch (Exception e) {
                String m = e.toString();
                if (m.contains("socket closed"))
                    System.out.println(" done");
                else
                    System.out.println("" + e);
            }
        });
        try { r.get(4, TimeUnit.SECONDS); } catch(TimeoutException ex) { /* ignored */ }
        try { s.close(); } catch (Exception e) { System.out.println(" close " + s + " failed: " + e); }
    }
}

with localhost.txt

> netstat -nao | findstr 5640
  TCP    127.0.0.1:51276        127.0.0.1:51277        HERGESTELLT     5640
  TCP    127.0.0.1:51277        127.0.0.1:51276        HERGESTELLT     5640
  TCP    127.0.0.1:51278        127.0.0.1:51279        HERGESTELLT     5640
  TCP    127.0.0.1:51279        127.0.0.1:51278        HERGESTELLT     5640
  TCP    127.0.0.1:51280        127.0.0.1:51281        HERGESTELLT     5640
  TCP    127.0.0.1:51281        127.0.0.1:51280        HERGESTELLT     5640
  TCP    127.0.0.1:51282        127.0.0.1:51283        HERGESTELLT     5640
  TCP    127.0.0.1:51283        127.0.0.1:51282        HERGESTELLT     5640
  TCP    127.0.0.1:51284        127.0.0.1:51285        HERGESTELLT     5640
  TCP    127.0.0.1:51285        127.0.0.1:51284        HERGESTELLT     5640

51276
accepting ... ServerSocket[addr=/127.0.0.1,localport=51276] done
51277
accepting ... ServerSocket[addr=/127.0.0.1,localport=51277] done
51278
accepting ... ServerSocket[addr=/127.0.0.1,localport=51278] done
51279
accepting ... ServerSocket[addr=/127.0.0.1,localport=51279] done

with wildcard.txt

> netstat -nao | findstr 7316
  TCP    127.0.0.1:51304        127.0.0.1:51305        HERGESTELLT     7316
  TCP    127.0.0.1:51305        127.0.0.1:51304        HERGESTELLT     7316
  TCP    127.0.0.1:51306        127.0.0.1:51307        HERGESTELLT     7316
  TCP    127.0.0.1:51307        127.0.0.1:51306        HERGESTELLT     7316
  TCP    127.0.0.1:51308        127.0.0.1:51309        HERGESTELLT     7316
  TCP    127.0.0.1:51309        127.0.0.1:51308        HERGESTELLT     7316
  TCP    127.0.0.1:51310        127.0.0.1:51311        HERGESTELLT     7316
  TCP    127.0.0.1:51311        127.0.0.1:51310        HERGESTELLT     7316
  TCP    127.0.0.1:51312        127.0.0.1:51313        HERGESTELLT     7316
  TCP    127.0.0.1:51313        127.0.0.1:51312        HERGESTELLT     7316
  
51304
accepting ... ServerSocket[addr=0.0.0.0/0.0.0.0,localport=51304] done
51305
Failed 51305: java.net.BindException: Address already in use: JVM_Bind
51306
accepting ... ServerSocket[addr=0.0.0.0/0.0.0.0,localport=51306] done
51307
Failed 51307: java.net.BindException: Address already in use: JVM_Bind