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();

	}

}

　

建立票池

package cn.ljs.FristSync;

public class SalerDemo01 extends Thread{

    private String name;
    private TicketsPool pool;

    public SalerDemo01(String name, TicketsPool pool){
        this.name = name;
        this.pool = pool;
    }

    public void run(){
        while (true){
            int num = pool.getTickets();
            if (num != ) {
                System.out.println(name+"卖了"+num);
            }else {
                return;
            }
        }

    }

    public static void main(String[] args) {

        TicketsPool pool = new TicketsPool();
        SalerDemo01 saler1 = new SalerDemo01("", pool);
        SalerDemo01 saler2 = new SalerDemo01("", pool);
        SalerDemo01 saler3 = new SalerDemo01("", pool);

        saler1.start();
        saler2.start();
        saler3.start();

    }

}

class TicketsPool{

    private int num = ;
    public int getTickets(){

        synchronized (this) {
            int tmp = num;
            num--;
            return tmp >  ? tmp:;
        }
    }

}