// 加在方法上面的同步鎖是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) {    // 類鎖    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() {    // 開始賣票    while (tick > 0) {      // 同步代碼塊      // 一把鎖 鑰匙      // 所有的線程 必須在這里排隊      synchronized (obj) {        if (tick > 0) {          System.out.println(getName() + "賣出了第【" + tick + "】張票");// 失去了cpu資源          tick--;        }      }      try {        Thread.sleep(100);      } catch (InterruptedException e) {        e.printStackTrace();      }    }  }}