synchronized 同步代码块，售票问题

package cn.ljs.FristSync;


public class SalerDemo extends Thread {
	
	static int tickets = 1000;
	String name;
	static Object lock = new Object();
	public SalerDemo(String name) {
		this.name = name;
	}
	public void run(){
		
		while(true){
			
			synchronized (lock) {
				if (tickets < 1) {
					return ;
				}
				System.out.println(name + ": " + tickets);
				tickets--;
			}
		}
	}
	
	public static void main(String[] args) {
		Thread t1 = new SalerDemo("saler1");
		Thread t2 = new SalerDemo("saler2");
		Thread t3 = new SalerDemo("saler3");
		t1.start();
		t2.start();
		t3.start();
		
	}
	
	
}