急求，有没有人帮忙注释一下代码？

package UI;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.util.HashMap;
import java.util.Map;

public class UDPService {

private static final int PORT = 20000;
private static final int BUFF_SIZE = 8192;
private DatagramSocket datagramSocket;
public UDPService() throws SocketException{
    datagramSocket = new DatagramSocket(PORT);
}
public void broadcast(String data) throws IOException {
    byte[] bytes = data.getBytes("UTF-8");
    DatagramPacket dp = new DatagramPacket(bytes, 0, bytes.length,
            InetAddress.getByName("255.255.255.255"), PORT);
    datagramSocket.send(dp);
}
public void send(String ip, int port, String data) throws IOException {
    byte[] bytes = data.getBytes("UTF-8");
    DatagramPacket dp = new DatagramPacket(bytes, 0, bytes.length,
            InetAddress.getByName(ip), port);
    datagramSocket.send(dp);
}
public Map<String, String> receive() throws IOException {
    byte[] buff = new byte[BUFF_SIZE];
    DatagramPacket dp = new DatagramPacket(buff, buff.length);
    datagramSocket.receive(dp);
    Map<String, String> map = new HashMap<String, String>(4);
    map.put("data", new String(buff, "UTF-8"));
    map.put("hostName", dp.getAddress().getHostName());
    map.put("hostAddr", dp.getAddress().getHostAddress());
    map.put("hostPort", dp.getPort() + "");
    return map;
}

}

就是用socket简单的udp广播通讯，局域网中同一个网段的接受