每一個類的實現： 首先是share，用於傳遞資訊和放置公用——

package mygame.shared;

public class Utilities {
    // set DEBUG = false and compile to stop debug messages
    final static boolean DEBUG = true;

    public static void printMsg(String msg)
 
 {
	if (DEBUG) {
	    System.out.println(msg);
	}
    }
}

接下來是客戶端

package mygame.client;//首先要聲名一個包

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

import mygame.shared.Utilities;

public class Client extends Thread {
    Socket clientSocket = null;
    /*thread類與runnable等程序執行緒操作相關 
    socket套接字用於實現client與其他類之間的通訊與資料傳遞
    此處聲名了一個socket為clientSocket*/
 


    public Client(Socket s) {
	clientSocket = s;//實現賦值的方法
    }

    public void run() {
	if (clientSocket == null) {
	    return;
	}

	PrintStream out = null;//定義輸出流為空

	Utilities.printMsg("creating output stream");//輸出這句話

	try {
	    out = new PrintStream(clientSocket.getOutputStream());
	    /*定義輸出流為getOut的套接字輸出流*/
 

	} catch (IOException e) {
	    System.err.println("Error binding output to socket, " + e); 
	    System.exit(1);
	}//用try+catch結構輸出異常並跳出

	Utilities.printMsg("writing current date");

	Date d = new Date();
	/*newdate也不一定是隻能輸出當年當月當日的本機時間
	可以直接使用 Date date = new Date(2016-1900,8-1,28);
	並且用systemoutp來輸出，但是要注意在年份上減去1900；
	或者使用Calendar物件加以構造
	Calendar c1 = Calendar.getInstance();
    c1.set(2016,8-1,28);*/
   
	out.println(d);

	try {          
	    out.close();
	    clientSocket.close();//關閉套接字
	} catch (IOException e) {
	}
    }

    protected void finalize() {
	if (clientSocket != null) {
	    try {
		clientSocket.close();
	    } catch (IOException e) {
	    }
	    clientSocket = null;
	}
    }  //finalize個人覺得用處不大
}

最後是server部分

package mygame.server;

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

import mygame.client.Client;
import mygame.shared.Utilities;
//由於已經有了client與utilities兩個類，需要把介面都放進來

public class Server {

    public static void main(String args[]) {
	ServerSocket serverSocket = null;//同樣聲名一個套接字

	Utilities.printMsg("creating server socket");
	
	try {
	    serverSocket = new ServerSocket(4444);//佔用介面4444
	} catch (IOException e) {
	    System.err.println("Unable to create server socket, " + e);
	    System.exit(1);
	}

	Utilities.printMsg("accepting client connections");

	while (true) {
	    try {
		Socket clientSocket = serverSocket.accept();//接受連線請求
		new Client(clientSocket).start();
	    } catch (IOException e) {
		System.err.println("Unable to accept socket connection, " + e); 
		System.exit(1);//報錯並輸出
	    }
	}
    }
}