How to Implement Peer-to-Peer Communication in Java?

// Java Program to Implement Server Side 
import java.io.*;
import java.net.*;

// Driver Class
public class Server {
      // Main Function
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(12345);
            System.out.println("Server started. Waiting for a client...");

            // Wait for a client to connect
            Socket clientSocket = serverSocket.accept();
            System.out.println("Client connected.");

            // Open input and output streams
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

            // Exchange data
            String message = in.readLine();
            System.out.println("Client: " + message);
            out.println("Hello from server!");

            // Close connections
            in.close();
            out.close();
            clientSocket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

// Java Program to Implement Client Side
import java.io.*;
import java.net.*;

// Driver Class
public class Client {
      // Main Function
    public static void main(String[] args) {
        try {
            Socket socket = new Socket("localhost", 12345);
            System.out.println("Connected to server.");

            // Open input and output streams
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

            // Exchange data
            out.println("Hello from client!");
            String response = in.readLine();
            System.out.println("Server: " + response);

            // Close connections
            in.close();
            out.close();
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}