private Timer timer = new Timer("Timer");

    public void start(){
        long delay1 = 1000L;
        long period1 = 1000L * 60L * 60L * 24L;
        long period2 = 60000L;

        timer.scheduleAtFixedRate(taskRecruit, delay1 , period1);
        timer.scheduleAtFixedRate(taskHoliday,delay2, period2);
        timer.scheduleAtFixedRate(taskTraining, delay3, period3);
    }

    private TimerTask taskRecruit = new TimerTask() {
        @Override
        public void run() {

        }
    };

    private TimerTask taskHoliday= new TimerTask() {
        @Override
        public void run() {

        }
    };

    private TimerTask taskTraining = new TimerTask() {
        @Override
        public void run() {
        }
    };

ScheduledExecutorService executorService = Executors.newScheduledThreadPool(3);
executorService.scheduleAtFixedRate(Tasks::taskRecruit, delay1, period1, TimeUnit.MILLISECONDS)
executorService.scheduleAtFixedRate(Tasks::taskHoliday, delay1, period1, TimeUnit.MILLISECONDS)
executorService.scheduleAtFixedRate(Tasks::taskTraining, delay1, period1, TimeUnit.MILLISECONDS)