Here you can find the source of isGregorianLeapYear(int gregorianYear)
public static final boolean isGregorianLeapYear(int gregorianYear)
//package com.java2s; //License from project: Mozilla Public License public class Main { public static final boolean isGregorianLeapYear(int gregorianYear) { return (((gregorianYear % 4) == 0) && (((gregorianYear % 100) != 0) || ((gregorianYear % 400) == 0))); }//from w ww .j a va2s. c o m }