關於線程同步問題

 class SalesLady {
    int memontoes, five, ten;

    public synchronized String ruleForSale(int num, int money) {
        String s = null;
        if (memontoes == 0)
            return "對不起，已經售完";
        if (money == 5) {
            memontoes--;
            five++;
            s = "給你票，" + "你的錢正好。";
        } else if (money == 10) {
            while (five < 1) {
                try {
                    System.out.println("" + num + "號顧客用10元購票，請等待");
                    wait();
                } catch (InterruptedException e) {
                }
            }
            memontoes--;
            five -= 1;
            ten++;
            s = "給你票，" + "找你5元。";
        }
        notifyAll();
        return s;
    }

    SalesLady(int m, int f, int t) {
        memontoes = m;
        five = f;
        ten = t;
    }
}

public class 八_5 extends java.applet.Applet {
    static SalesLady saleslady = new SalesLady(14, 0, 0);
    public void start() {
        int moneies[] = { 10, 10, 5, 10, 5, 10, 5, 5, 10, 5, 10, 5, 5, 10, 5};
        Thread[] aThreadArray = new Thread[20];
        System.out.println("現在開始售票：");
        for (int i = 0; i < moneies.length; i++) {
            aThreadArray[i] = new Thread(new CustomerClass(i + 1, moneies[i])); aThreadArray[i].start(); } WhileLoop: while (true) {
            for (int i = 0; i < moneies.length; i++)
                if (aThreadArray[i].isAlive())
                    continue WhileLoop;
            break;
        }
        System.out.println("票已售完");
    }
}

class CustomerClass implements Runnable {
    int num, money;

    public void run() {
        try {
            Thread.sleep(10);
        }
        catch (InterruptedException e) {
        }
        System.out.println("我是" + num + "號顧客，用" + money + "元購票,售票員說："
                + 八_5.saleslady.ruleForSale(num, money));
    }

    CustomerClass(int n, int m) {
        num = n;
        money = m;
    }
}