UDP client/server

The UDP client/server applications are similar in structure to the structure used for TCP client/server applications. On the server side, a UDP server socket is created, which waits for client requests. The client will create a corresponding UDP socket and use it to send a message to the server. The server can then process the request and send back a response.

A UDP client/server will use the DatagramSocket class for the socket and a DatagramPacket to hold the message. There is no restriction on the message's content type. In our examples, we will be using a text message.

The UDP server application

Our server is defined next. The constructor will perform the work of the server:

public class UDPServer {
    public UDPServer() {
        System.out.println("UDP Server Started");
        ...
        System.out.println("UDP Server Terminating");
    }

    public static void main(String[] args) {
        new UDPServer();
    }
}

In the constructor's try-with-resources block, we create...