Server.java

import java.net.*;
import java.io.*;
import java.util.Date;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

// One thread per connection, this is it
class ServerThread extends Thread {

    // The socket passed from the creator
    private Socket socket = null;

    public ServerThread(Socket socket) {

        this.socket = socket;

    }

    // Handle the connection
    public void run() {

        try {

        // Attach a printer to the socket's output stream
        PrintWriter socketOut = new PrintWriter(socket.getOutputStream(), true);

        // Get the date and time
        DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss dd/MM/yyyy");
        Date date = new Date();

        // Send the date and time to the client
        socketOut.println(dateFormat.format(date));

        // Close things
        socketOut.close();
        socket.close();

    } catch (IOException e) {

        e.printStackTrace();

        }
    }
}

// The server
public class Server {

    public static void main(String[] args) throws IOException {

    // The server socket, connections arrive here
        ServerSocket serverSocket = null;

        try {

        // Listen on on port 7777
            serverSocket = new ServerSocket(7777);

        } catch (IOException e) {

            System.err.println("Could not listen on port: 7777");
            System.exit(-1);

        }

    // Loop forever
        while (true) {

        /*
         * Several things going on with this line of code:
         * 1. Accept a connection (returns a new socket)
         * 2. Create a new thread of type ServerThread
         * 3. Call start on the new thread
         */
        new ServerThread(serverSocket.accept()).start();
        }
    }
}