Here you can find the source of isLeapYear(int year)
public static boolean isLeapYear(int year)
//package com.java2s; //License from project: Apache License public class Main { private static transient int gregoranCutoverYear = 1582; public static boolean isLeapYear(int year) { return year >= gregoranCutoverYear ? ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0))) : (year % 4 == 0);//from www .j a v a 2 s . co m } }