多线程写法，消除同步bug

public class Demo01 implements Runnable {
private int ticket = 10;

@Override
public void run() {
	for (int i = 0; i < 10; i++) {
		synchronized (this) {
			if (ticket > 0) {
				try {
					Thread.sleep(1000);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println(Thread.currentThread().getName()
						+ ",正在卖出第" + (this.ticket--) + "张票！");
 
			}
		}
	}
}

public static void main(String[] args) {
Demo01 mt = new Demo01();
new Thread(mt, "售票员A").start();
new Thread(mt, "售票员B").start();
new Thread(mt, "售票员C").start();
}