Что требуется валидатору?

package com.javarush.task.task16.task1617;

/*
Отсчет на гонках
*/

public class Solution {
    public static volatile int numSeconds = 3;

    public static void main(String[] args) throws InterruptedException {
        RacingClock clock = new RacingClock();
        //add your code here - добавь код тут
        Thread.sleep(3500);
        clock.interrupt();
    }

    public static class RacingClock extends Thread {
        public RacingClock() {
            start();
        }


        public void run() {
            //add your code here - добавь код тут
            // int counter = numSeconds;
            double count = 0;
            try {
                while (! (numSeconds == 0)) {
                    System.out.print(numSeconds + " ");
                    Solution.numSeconds--;
                    Thread.sleep(500);
                    count += 0.5;
                    Thread.sleep(500);
                    count += 0.5;

                }
                if ((numSeconds == 0) & (count < 4)) {
                    System.out.print("Марш");
                }
            } catch (InterruptedException e) {System.out.println("Прервано!");}
        }}
}

package com.javarush.task.task16.task1617;

/*
Отсчет на гонках
*/

public class Solution {
    public static volatile int numSeconds = 3;

    public static void main(String[] args) throws InterruptedException {
        RacingClock clock = new RacingClock();
        //add your code here - добавь код тут
        Thread.sleep(3500);
        clock.interrupt();
    }

    public static class RacingClock extends Thread {
        public RacingClock() {
            start();
        }


        public void run() {
            //add your code here - добавь код тут
            // int counter = numSeconds;

                while (! (numSeconds == 0)) {
                    System.out.print(numSeconds + " ");
                    Solution.numSeconds--;
                    try {
                        Thread.sleep(1000);
                    if ((numSeconds == 0) && !Thread.currentThread().isInterrupted()) {
                            System.out.print("Марш");

                }
            } catch (InterruptedException e) {System.out.println("Прервано!");}
        }}
}}