UDPClient

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

class UDPClient
{
   public static void main(String args[]) throws Exception
   {
    DatagramSocket socket = new DatagramSocket(65530);
        DatagramPacket packet = new DatagramPacket(new byte[256] , 256);
    FileWriter outputStream;
    BufferedWriter out;

    String file_string;

        while(true){
            socket.receive(packet);
            file_string = new String(packet.getData());

            file_string = file_string.replaceAll("[^\\d.,]", "");

            System.out.println(file_string);

            outputStream = new FileWriter("file1.txt",false);
            out = new BufferedWriter(outputStream);

            out.write(file_string);
            out.close();
        }
    }
}