UDP Socket Server

package catalog;

import java.net.*;

public class CatalogServer extends Thread {

    final static int port = 8532;
    final static int taille = 1024;
    final static byte buffer[] = new byte[taille];
    private String queryStr;
    String songList = new String("Black or White.mp3Love Piano.mp3La Fleur.mp3Le Bapteme.mp3Amour Mathematique.mp3");
    int length;
    byte buffer1[];
    String selectedSong;

    public String getSelectedSong() {
        return selectedSong;
    }

    public void setSelectedSong(String selectedSong) {
        this.selectedSong = selectedSong;
    }


    public static void main(String argv[]) {

        CatalogServer cs = new CatalogServer();
        cs.start();
    }

    public void run() {
        try {
            DatagramSocket socket = new DatagramSocket(port);


            while (true) {
                //---------- serv recv ---------------
                DatagramPacket data = new DatagramPacket(buffer, buffer.length);
                socket.receive(data);
                queryStr = new String(data.getData(), 0, data.getLength());
                System.out.println(queryStr);


                // --------serv send ------------
                if (queryStr.equals("Song Request")) {
                    length = songList.length();
                    buffer1 = songList.getBytes();
                    DatagramPacket dataSent = new DatagramPacket(buffer1, length,
                            data.getAddress(), data.getPort());
                    socket.send(dataSent);
                }

                //---------- recv song -------------
                else {
                 //   socket.receive(data);
                 //   queryStr = new String(data.getData(), 0, data.getLength());
                    setSelectedSong(queryStr);                   
                }

                //System.out.println(data.getAddress());
            }

        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}