I have an ArrayList which contains every day of the week. The function takes two arguments: the current day of the week and an integer value to increment the number of days by.

For example, if the current day is Monday and the integer value is 3, it should return Thursday.

It also needs to be able to "loop around", so if the current day is Sunday and the value is 2, it should return Tuesday.

Below is what I have so far, it only returns the currentDay. I'm really new to Java so any assistance would be great.

import java.util.ArrayList;

public class DaysOfWeek {

    public static void main(String[] args) {
        System.out.println(calcDay("Tue", 2));
    }

    public static String calcDay(String currentDay, int incrementDays) {

        ArrayList days = new ArrayList();

        days.add(0,"mon");
        days.add(1,"tue");
        days.add(2,"wed");
        days.add(3,"thu");
        days.add(4,"fri");
        days.add(5,"sat");
        days.add(6,"sun");

        if((days.contains(currentDay.toLowerCase())) && ((incrementDays >= 0) && (incrementDays <= 500))) {

           for(int i = days.indexOf(currentDay.toLowerCase()); i < incrementDays+1; i++) {
                String newDay = days.get(i);
                return newDay;
            }
        } return "Invalid";
    }
}