这段 Java 代码的线程锁对象为 final 的，为何只有一个线程会被执行？

Question

 

• public class WindowTestThree {
      public static void main(String[] args) {
          WindowThree w = new WindowThree();
          Thread w1 = new Thread(w);
          Thread w2 = new Thread(w);
          Thread w3 = new Thread(w);
          w1.start();
          w2.start();
          w3.start();
      }
  }
  
  class WindowThree implements Runnable {
      // private static int ticket = 100;
      private int ticket = 100;
      // final Object obj = new Object();
      Object obj = new Object();
  
      @Override
      public void run() {
          while (true) {
              synchronized (obj) {
                  if (ticket > 0) {
                      try {
                          Thread.sleep(100);
                      } catch (InterruptedException e) {
                          e.printStackTrace();
                      }
                      System.out.println(Thread.currentThread().getName() + "：成功售出一张票，剩余" + ticket + "张票");
                      ticket--;
                  } else {
                      break;
                  }
              }
          }
      }
  }

   

Answer 1

代码没问题，只不过一直被同一个代码抢占，这是正常现象。