HostFinder

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
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.logging.Level;
import java.util.logging.Logger;


/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author Oplus
 */
public class main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        try {
            main obj = new main();
            obj.run(args);
        } catch (Exception ex) {
            Logger.getLogger(main.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    public void run(String[] args) throws Exception {
        String IP = "192.168.1.";
        String Command = "Hello!\r\n";
        ExecutorService executor = Executors.newFixedThreadPool(20);
        List<Future<result>> list = new ArrayList<Future<result>>();
        for (int i = 0; i < 255; i++) {
            String ip = IP + String.valueOf(i);
            Callable<result> task = new scanner(ip, 9092, Command);
            Future<result> submit = executor.submit(task);
            list.add(submit);
        }
        for (Future<result> future : list) {
            try {
                result r = future.get();
                if(r.response != null){
                    System.out.println(r.ip + " Said : " + r.response);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (ExecutionException e) {
                e.printStackTrace();
            }
        }
        executor.shutdown();
        executor.awaitTermination(Long.MAX_VALUE,TimeUnit.NANOSECONDS);
        if(list.size() == 0)
            System.out.println("NotFound !");
        else
            System.out.println("Found !");
    }

    class result {

        public String ip;
        public String response;
    }

    class scanner implements Callable<result> {

        private String ip;
        private String cmd;
        private int port;

        public scanner(String ip, int port, String cmd) {
            this.ip = ip;
            this.cmd = cmd;
            this.port = port;
        }

        @Override
        public result call() throws Exception {
            result t = new result();
            t.ip = this.ip;
            String result = SendCommand(this.ip, this.cmd, true);
            t.response = result;
            return t;
        }

        private String SendCommand(String IP, String CMD, boolean output) {
            try {
                Socket socket = new Socket();
                socket.connect(new InetSocketAddress(IP, port), 200);

                InputStream inputStream = socket.getInputStream();
                OutputStream outputStream = socket.getOutputStream();

                BufferedInputStream reader = new BufferedInputStream(inputStream);
                PrintWriter writer = new PrintWriter(outputStream);
                writer.write(CMD);
                writer.flush();
                if (output == true) {
                    int timeout = 0;
                    while (reader.available() <= 0) {
                        Thread.sleep(200);
                        if (timeout == 5) {
                            return null;
                        }
                        timeout++;
                    }

                    int BytesRead = 0;
                    byte[] buffer = new byte[1024];
                    String response = "";
                    while ((BytesRead = reader.read(buffer)) != -1) {
                        response += new String(buffer, 0, BytesRead);
                    }
                    if(response.equals("")){
                        return null;
                    }
                    return response;
                }
                return null;

            } catch (Exception e) {
                return null;
            }
        }
    }

}