java多线程（4）模拟排队叫号程序，不能出现交替执行的结果

package com.javaconcurrencyprogramming.chapter1;

/**
 * @description: 模拟有错误的排队叫号程序
 * @author: 
 * @create: 
 **/

public class TicketWindow extends Thread{

    //柜台名称
    private final String name;

    //最多受理50笔业务
    private static final int MAX = 500;

   // private int index = 1;
    private static int index = 1;

    public TicketWindow(String name){
        this.name = name;
    }

    @Override
    public void run(){
        while (index <= MAX){

            System.out.println("柜台：" + name + " 当前的号码是：" + (index++));
        }
    }

    public static void main(String[] args) {
        TicketWindow ticketWindow1 = new TicketWindow("一号出号机");
        ticketWindow1.start();

        TicketWindow ticketWindow2 = new TicketWindow("一号出号机");
        ticketWindow2.start();

        TicketWindow ticketWindow3 = new TicketWindow("一号出号机");
        ticketWindow3.start();

        TicketWindow ticketWindow4 = new TicketWindow("一号出号机");
        ticketWindow4.start();
    }

}