Java UDP BroadCating.

sample code:

public class BroadcastingClient {
    private static DatagramSocket socket = null;
 
    public static void main(String[] args) throws IOException {
        broadcast("Hello", InetAddress.getByName("255.255.255.255"));
    }
 
    public static void broadcast(
      String broadcastMessage, InetAddress address) throws IOException {
        socket = new DatagramSocket();
        socket.setBroadcast(true);
 
        byte[] buffer = broadcastMessage.getBytes();
 
        DatagramPacket packet 
          = new DatagramPacket(buffer, buffer.length, address, 4445);
        socket.send(packet);
        socket.close();
    }
}

list broadcast address:

    List<InetAddress> listAllBroadcastAddresses() throws SocketException {
        List<InetAddress> broadcastList = new ArrayList<InetAddress>();
        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
        while (interfaces.hasMoreElements()) {
            NetworkInterface networkInterface = interfaces.nextElement();
            if (networkInterface.isLoopback() || !networkInterface.isUp()) {
                continue;
            }
            networkInterface.getInterfaceAddresses().stream().map(a -> a.getBroadcast()).filter(Objects::nonNull)
                    .forEach(broadcastList::add);
        }
        return broadcastList;
    }