public class BoundedCounter {
    private int value;
    private int upperLimit;

    public BoundedCounter(int upperLimit) {
        this.upperLimit = upperLimit;
        this.value = 0;
    }

    public void next() {
        if (this.value < this.upperLimit) {
            this.value++;
        } else {
            this.value = 0;
        }
    }

    public String toString() {
        if (this.value < 10) {
            return "0" + this.value;
        } else {
            return "" + this.value;
        }
    }

    public int getValue() {
        return this.value;
    }

    public void setValue(int number) {
        if (number > 0 && number <= this.upperLimit) {
            this.value = number;
        }
    }
}

-----------------------------

public class Clock {
    private BoundedCounter hours;
    private BoundedCounter minutes;
    private BoundedCounter seconds;

    public Clock(int hoursAtBeginning, int minutesAtBeginning, int secondsAtBeginning) {
        // the counters that represent hours, minutes and seconds are created and set to have the correct initial values
        BoundedCounter hours = new BoundedCounter(23);
        hours.setValue(hoursAtBeginning);
        BoundedCounter minutes = new BoundedCounter(59);
        minutes.setValue(minutesAtBeginning);
        BoundedCounter seconds = new BoundedCounter(59);
        seconds.setValue(secondsAtBeginning);
        //System.out.println(hours + " " + minutes + " " + seconds);
    }

    public void tick() {
        seconds.setValue(seconds.getValue() + 1);
    }

    public String toString() {
        return hours + ":" + minutes + ":" + seconds;
    }
}


-------------------------------------

public class Main {
    public static void main(String[] args) {
        Clock clock = new Clock(23, 59, 50);

        System.out.println(clock);

//        int i = 0;
//        while (i < 20) {
//            System.out.println(clock);
//            clock.tick();
//            i++;
//        }
    }
}