锁同步代码块

package suo;

public class TextSynchronized {
    public static void main(String[] args) {
        RunnableeImpl a=new RunnableeImpl();
        Thread q1 = new Thread(a);
        Thread q2 = new Thread(a);
        Thread q3 = new Thread(a);
        q1.start();
        q2.start();
        q3.start();
    }
}

package suo;

public class RunnableeImpl implements Runnable {
    private int a = 100;

    Object b = new Object();

    @Override
    public void run() {
        while (true) {
            synchronized (b) {
                if (a > 0) {
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"-->正在卖第"+a+"张票");
                    a--;
                }
            }

        }
    }
}