public class Demo {
    public static void main(String[] args) throws Exception {
        XPCounter counter = new XPCounter();
        int actionTimer = 0;
        int xpGained = 0;

        while(true) {
            if(++actionTimer > 5) {
                actionTimer = 0;
                xpGained++;
            }

            int xpPerHour = counter.calculateXpPerHour(xpGained);
            System.out.printf("XP Per Hour: \t%d%n", xpPerHour);
            Thread.sleep(60);
        }
    }
}

class XPCounter {
    private final long startTime = System.currentTimeMillis();

    int calculateXpPerHour(int xpGained) {
        long elapsedMilliseconds = System.currentTimeMillis() - startTime;
        boolean minuteHasPassed = elapsedMilliseconds >= 60_000;

        int xpPerHour;
        if(minuteHasPassed) {
            double elapsedHours = (double) elapsedMilliseconds / 3_600_000d;
            xpPerHour = (int) (xpGained / elapsedHours);
        } else {
            xpPerHour = xpGained * 60;
        }

        return xpPerHour;
    }
}