代码如下:
public class Ticket1 implements Runnable {
    private int tickets = 100;

    @Override
    public void run() {

        while (tickets > 0) {
            synchronized (Ticket.class) {
                if (tickets > 0) {
                    tickets--;
                    System.out.println(Thread.currentThread().getName() + "正在卖票，还剩下" + tickets + "张");
                }
            }
            try {
                // 休眠一秒，让执行的效果更明显
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }


    public static void main(String[] args) {
        Ticket1 ticket = new Ticket1();

        Thread t1 = new Thread(ticket, "窗口一：");
        Thread t2 = new Thread(ticket, "窗口二：");
        Thread t3 = new Thread(ticket, "窗口三：");

        t1.start();
        t2.start();
        t3.start();
    }
}