@Override
    public boolean isLeapYear(long prolepticYear) {
        long lastTwoDigits = prolepticYear % 100;
        return Math.abs(lastTwoDigits) == 99 || (prolepticYear % 400 != 0 && (lastTwoDigits == 0 || lastTwoDigits % 6 == 0));
    }
@ Override public boolean isLeapYear ( long prolepticYear ) { long lastTwoDigits = prolepticYear % 100 ; return Math . abs ( lastTwoDigits ) == 99 || ( prolepticYear % 400 != 0 && ( lastTwoDigits == 0 || lastTwoDigits % 6 == 0 ) ) ; }
Checks if the specified year is a leap year.
<p>
In general, a year is a leap year if the last two digits are divisible by 6 without remainder, or are 99.
Years with the last two digits of 00 are also leap years, with the exception of years divisible by 400, which are not.
<p>
For example, 2012 is a leap year because the last two digits (12) are divisible by 6.
1999 is a leap year as the last two digits are both 9's (99).
1900 is a leap year as the last two digits are both 0's (00), however 2000 was not a leap year as it is divisible by 400.
The year 0 is not a leap year.

@param prolepticYear  the proleptic-year to check, not validated for range
@return true if the year is a leap year