// 加在方法上面的同步锁是this
  public synchronized void print() {
    System.out.println("同步方法");
    try {
      Thread.sleep(3000);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
  }

public synchronized void print(String msg) {
    // 类锁
    synchronized (MyThread.class) {
      System.out.println(msg);
      try {
        Thread.sleep(3000);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }

public class Window extends Thread {

  public Window(String name) {
    super(name);
  }

  static int tick = 100;
  static String obj = new String();

  @Override
  public void run() {
    // 开始卖票
    while (tick > 0) {
      // 同步代码块
      // 一把锁 钥匙
      // 所有的线程 必须在这里排队
      synchronized (obj) {
        if (tick > 0) {
          System.out.println(getName() + "卖出了第【" + tick + "】张票");// 失去了cpu资源
          tick--;
        }
      }
      try {
        Thread.sleep(100);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }

  }
}