Java - can't read UDP socket from port/ip

I need to read from an ip/port, through UDP and I can't. From an external utility, I see that the reader (RFID) reads correctly from said port/ip through UDP. Now, I want to read it from java and I can't (I clarify that it is the first time that I am going to read from a port/ip through java). My code is the following, I hope you can guide me:

package test_rfid_udp;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class Test_RFID_UDP {
  public static void main(String args[]) {
    try {
      int port = 2000;

      // Create a socket to listen on the port.
      DatagramSocket dsocket = new DatagramSocket();

      // Create a buffer to read datagrams into. If a
      // packet is larger than this buffer, the
      // excess will simply be discarded!
      byte[] buffer = new byte[2048];

      // Create a packet to receive data into the buffer
      InetAddress address = InetAddress.getByName("192.168.0.77");
      DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, 2000);

      // Now loop forever, waiting to receive packets and printing them.
      while (true) {
        // Wait to receive a datagram
        dsocket.receive(packet);

        // Convert the contents to a string, and display them
        String msg = new String(buffer, 0, packet.getLength());
        System.out.println(packet.getAddress().getHostName() + ": "
        + msg);

        // Reset the length of the packet before reusing it.
        packet.setLength(buffer.length);
      }
    } catch (Exception e) {
      System.err.println(e);
    }
  }
}

I also attach an image of the readings made with the utility. I hope you can help me.

Thank you