Server

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.nio.channels.DatagramChannel;

public class Server3 extends Thread{

    byte[] sendData = new byte[50];
    boolean isRunning;
    InetAddress ipAddr;
    int portNb;
    DatagramSocket sendSock;

    public Server3(InetAddress ipAddr, int portNb) throws SocketException {
        super();
        this.ipAddr = ipAddr;
        this.portNb = portNb;
        sendSock = new DatagramSocket();
        DatagramChannel channel = null;
        try {
            channel = DatagramChannel.open();
        } catch (IOException e) {
            e.printStackTrace();
        }
        sendSock = channel.socket();
        sendSock.setReuseAddress(true);
    }

    @Override
    public void run() {

        while(isRunning){

            sendData = "server msg here".getBytes();

            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, ipAddr, portNb);
            try {

                sendSock.send(sendPacket);
                Thread.sleep(1000);
                System.out.println("sent msg");

            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }
    }

    public void startSending(){
        isRunning=true;
        start();
    }

    public void stopReceiving(){
        isRunning=false;
    }

    public static void main(String[] args) throws IOException {
        Server3 s = new  Server3(InetAddress.getByName("10.0.2.2"),57111);
        s.startSending();

    }
}