多线程简单实现，会产生不同步问题。

class MyThread implements Runnable {
	private int ticket = 30;

	public void run() {
		for (int x = 0; x < 5; x++) {
			if (this.ticket > 0) {
				try {
					Thread.sleep(2000);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				System.out.println("卖票，ticket =" + this.ticket--);
			}
		}
	}
}

public class TestDemo2 {

	public static void main(String[] args) {
		MyThread mt = new MyThread();
		new Thread(mt).start();
		new Thread(mt).start();
		new Thread(mt).start();

	}
}