package com.company;

import java.net.*;
import java.io.*;

class ServerThread implements Runnable{

    Thread t;

    ServerThread(DatagramSocket sock, DatagramPacket incoming) throws IOException {
        t=new Thread(this);
        t.start();

        byte[] data = incoming.getData();
        String s = new String(data, 0, incoming.getLength());

        System.out.println(incoming.getAddress().getHostAddress()+" : "+incoming.getPort()+" - "+s);

        s="OK: "+s;

        DatagramPacket dp = new DatagramPacket(s.getBytes(), s.getBytes().length, incoming.getAddress(), incoming.getPort());
        sock.send(dp);
    }

    @Override
    public void run() {

    }
}

public class Main {

    private static DatagramSocket sock = null;

    public static void main(String[] args) {
        try{
            sock = new DatagramSocket(45000);

            byte[] buffer = new byte[65536];
            DatagramPacket incoming = new DatagramPacket(buffer, buffer.length);

            System.out.println("Utworzono gniazdo serwera. Oczekiwanie na dane");

            while(true){
                sock.receive(incoming);

                ServerThread st=new ServerThread(sock, incoming);
                st.run();
            }

        }
        catch (IOException e){
            System.err.println("IOException "+e);
        }
    }
}