Почему код не верен?

public static class Apteka implements Runnable {

        @Override
        public void run() {
            while (!isStopped) {
                drugsController.buy(getRandomDrug(), getRandomCount());
                waitAMoment();
                try {
                    Thread.sleep(300);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static class Person implements Runnable {

        @Override
        public void run() {
            while (!isStopped) {
                drugsController.sell(getRandomDrug(), getRandomCount());
                waitAMoment();
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }