现实中也存在这样的情况：

模拟一个火车站的售票系统，假如当日从A地发往B地的火车票只有10张，且允许所有窗口卖这10张票，每一个窗口也相当于一个线程。

1、Runnable接口实现

public class Main {

  public static void main(String[] args) {

    Test m = new Test();

    Thread w1 = new Thread(m, "window 1");
    Thread w2 = new Thread(m, "window 2");
    Thread w3 = new Thread(m, "window 3");

    w1.start();
    w2.start();
    w3.start();

  }
}

class Test implements Runnable {
  private int n = 10;

  public void run() {
    while (n > 0) {
      System.out.println(n-- + " is saled by " + Thread.currentThread().getName());
    }
  }
}

2、Thread子类实现

public class Main {

  public static void main(String[] args) {

    Ticket t = new Ticket();
    Test w1 = new Test(t,"window 1");
    Test w2 = new Test(t,"window 2");
    Test w3 = new Test(t,"window 3");
    
    w1.start();
    w2.start();
    w3.start();
  }
}

class Ticket {
  int tic = 10;
}
class Test extends Thread{
  private Ticket tick;
  public Test(Ticket tick, String name){
    super(name);
    this.tick = tick;
  }
  public void run(){
    while(tick.tic > 0){
      System.out.println(tick.tic --  + " is saled by " + Thread.currentThread().getName());
    }
  }
}