ServerSocket and Socket classes

Java provides us two classes ServerSocket and Socket to create a Client/Server architecture. We use ServerSocket to create a server and the Socket class to create clients. The Socket class sends requests to the ServerSocket class and the ServerSocket responds according to the reqeust being sent by the client. Examples of both ServerSocket and Socket classes are as follows :

// ServerSocket Example


import java.io.*;
import java.net.*;

public class Server
{
        private ServerSocket server;
        private Socket client;
        private BufferedReader readClient;

        public Server()
        {
                try
                {
                        server = new ServerSocket(9999);
                        System.out.println("Server Started...");

                        client = server.accept();
                        System.out.println("Client Connected..");

                        readClient = new BufferedReader(new InputStreamReader(client.getInputStream()));

                        System.out.println(readClient.readLine());

                        readClient.close();
                        server.close();
                }
                catch(Exception e)
                {
                        System.out.println(e);
                }
        }
        public static void main(String[] args)
        {
                new Server();
        }
}


// Socket Example


import java.io.*;
import java.net.*;

public class Client
{
        private Socket client;
        private PrintWriter write_To_Server;

        public Client()
        {
                try
                {
                        client = new Socket("localhost", 9999);
                        write_To_Server = new PrintWriter(client.getOutputStream());

                        write_To_Server.println("Programming World");

                        write_To_Server.close();
                        client.close();
                }
                catch(Exception e)
                {
                        System.out.println(e);
                }
        }
        public static void main(String[] args)
        {
                new Client();
        }
}