Java ServerSocket Class

// Java program demonstrates the 
// working of server-side programming
// using ServerSocket class
import java.io.*;
import java.net.*;
import java.io.*;
import java.net.*;

public class MyServer {
    public static void main(String[] args) {
        try {
            System.out.println("Starting server...");

            // Create a ServerSocket listening on port 6666
            ServerSocket ss = new ServerSocket(6666);
            System.out.println("Server started. Listening on port 6666...");

            // Accept a connection from a client
            Socket s = ss.accept();
            System.out.println("Client connected!");

            // Read the message from the client
            DataInputStream d = new DataInputStream(s.getInputStream());
            String str = d.readUTF();
            System.out.println("Message: " + str);

            // Close the socket
            ss.close();
        } catch (Exception e) {
            System.out.println("Server Error: " + e);
        }
    }
}

// Java program demonstrates the 
// working of client-side programming
// using ServerSocket class
import java.io.*;
import java.net.*;

public class MyClient {

    // Main driver method
    public static void main(String[] args) {

        // Try block to check if exception occurs
        try {

            // Creating Socket class object and
            // initializing Socket
            Socket s = new Socket("localhost", 6666);

            DataOutputStream d = new DataOutputStream(
                s.getOutputStream());

            // Message to be displayed
            d.writeUTF("Hello GFG Readers!");

            // Flushing out internal buffers,
            // optimizing for better performance
            d.flush();

            // Closing the connections

            // Closing DataOutputStream
            d.close();
            // Closing socket
            s.close();
        }

        // Catch block to handle exceptions
        catch (Exception e) {

            // Print the exception on the console
            System.out.println(e);
        }
    }
}