public boolean isLeapYear(int year){
        if(year % 400 == 0){
            return true;
        }
        if(year % 4 == 0 && year % 100 != 0){
            return true;
        }
        return false;
    }
Number of days between two valid dates
The idea is to get number of days from 00/00/0000 for both the dates and find the
difference between them.
src/com/interview/misc/DayDifferenceBetweenTwoDates.java