Example of Socket and ServerSocket on local host connection

Client.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package sockets;

import java.net.Socket;
import java.io.*;
import java.util.Arrays;

/**
 *
 * @author kamil
 */
public class Client {

    private Socket socket;
    private BufferedReader input;
    private PrintWriter output;
    private String prefix = "[Clinet] >> ";
    
    public Client(String ip, int port) {
        try {
            // Establish a connection
            socket = new Socket(ip, port);
            System.out.println(prefix + "Connected!");
            
            // Take input from the termianl
            input = new BufferedReader(new InputStreamReader(System.in));

            // Send output to the socket
            output = new PrintWriter(socket.getOutputStream(), true);
            
        } catch (IOException e) {
            System.out.println(prefix + "ERROR!");
            System.out.println(e.getMessage());
        }
        
        // Give termianl access
        showTermianlAccess();
    }
    
    private void showTermianlAccess() {
        String line = "";
        String[] cmdList = {Command.quit.toString(), Command.send.toString() + " <message>"};
        
        try {
            while (line.equalsIgnoreCase(Command.quit.toString()) == false) {
                // Take input from the termianl
                System.out.println(prefix + "Commands > " + Arrays.toString(cmdList));
                line = input.readLine();
                
                // Check if the first words is a send commands
                String[] splitLine = line.split(" ");
                if (splitLine.length > 1 && splitLine[0].equalsIgnoreCase(Command.send.toString())) {
                    // Send the message to the socket
                    output.println(splitLine[1]);
                    System.out.println("Message send!\n");
                    
                } else {
                    System.out.println("Input Error! Try again\n");
                } 
                           
            } 
        } catch (IOException e) {
            System.out.println(prefix + "Error!");
            System.out.println(e.getMessage());
        }
    }    
}

Command.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package sockets;

/**
 *
 * @author kamil
 */
public enum Command {
    quit("Quit"), send("Send");

    private String msg;      

    private Command(String msg) {
        this.msg = msg;
    }

    @Override
    public String toString() {
        return msg;
    }
}

Server.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package sockets;

import java.net.ServerSocket;
import java.net.Socket;
import java.io.*;

/**
 *
 * @author kamil
 */
public class Server {
        
    private ServerSocket serverSocket;
    private Socket socket;
    private BufferedReader input;
    private PrintWriter output;
    private String prefix = "[Server] >> ";
    
    public Server(int port) {
        try {
            // Create a server socket
            serverSocket = new ServerSocket(port);
            System.out.println(prefix + "Server is starting...");
            System.out.println(prefix + "Server is waiting for a client...");
            
            // Wait until a connection from a clinet
            socket = serverSocket.accept();
            System.out.println(prefix + "Server is connected to the client!");
            
            // Load input and output
            input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            output = new PrintWriter(socket.getOutputStream(), true);
                    
        } catch (IOException e) {
            System.out.println(prefix + "Server Error!");
            System.out.println(e.getMessage());
        }
        
        runServerClientCommunication();
    }
    
    private void runServerClientCommunication() {
        String line = "";
        
        try {
            while (line.equalsIgnoreCase(Command.quit.toString()) == false) {               
                // Read input from client
                line = input.readLine();
                System.out.println(prefix + "Client said: " + line);
            }
            
            // Close the ports
            System.out.println(prefix + "Closting connection!");
            input.close();
            output.close();
            socket.close();
            serverSocket.close();
            
        } catch (IOException e) {
            System.out.println(prefix + "Server Error!");
            System.out.println(e.getMessage());
        }
    }
}

StartServerClient.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package sockets;

/**
 *
 * @author kamil
 */
public class StartServerClient {
    
    private static final String IP = "127.0.0.1"; // Local host
    private static final int PORT = 5000;
    
    public static void main(String[] args) {
        // Start the server fist on new thread
        new Thread(new Runnable() {
            @Override
            public void run() {
                new Server(PORT);
            }
        }).start();
        
        // Delay
        try {Thread.sleep(2000);} catch (Exception e) {}
        
        // Start the clinet on a new thread
        new Thread(new Runnable() {
            @Override
            public void run() {
                new Client(IP, PORT);
            }
        }).start();
    }
}