Gregorian calendar

 package com.company;

import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;

public class CWH_99_GregorianCalendarClass {
    public static void main(String[] args) {
        Date d= new Date();
        GregorianCalendar g= new GregorianCalendar();
        System.out.println(g.isLeapYear(1900));
//        System.out.println(g.setGregorianChange());
        for(int i=0;i<100;i++){
            System.out.println(TimeZone.getAvailableIDs()[i]);
        }
    }
}