Java's synchronized block processing thread safety issues of class inheritance Thread

com.atguigu.java Package Penalty for; 

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* / 
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* synchronous code block address security thread Thread class way of inheritance 
* 
* Example: Create three ticket windows, the total number of votes for the 100 using inheritance Thread. class way 
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* Note: the inheritance thread class to create multi-threaded mode, this acts as a synchronization monitors used with caution, given the current class act as synchronization monitors. 
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* / 
Class Window2 the extends the Thread { 


    Private static int Ticket = 100; 

    Private static Object obj = new new Object (); 

    @Override 
    public void RUN () { 

        the while (to true) { 
            // correct 
// the synchronized (obj) { 
            the synchronized (Window2.class) {// Class clazz = Window2.class, Window2.class only loaded once 
                // wrong way: this represents t1, t2, t3 three objects 
// synchronized (this) {

                if(ticket > 0){

                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    System.out.println(getName() + "：卖票，票号为：" + ticket);
                    ticket--;
                }else{
                    break;
                }
            }

        }

    }
}


public class WindowTest2 {
    public static void main(String[] args) {
        Window2 t1 = new Window2();
        Window2 t2 = new Window2();
        Window2 t3 = new Window2();


        t1.setName ( "window. 1"); 
        t2.setName ( "window 2"); 
        t3.setName ( "window. 3"); 

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

    } 
}