import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;
import java.util.*;
public class CalendarExample {

/**
* Helper utility used to print a String to STDOUT.
* @param s String that will be printed to STDOUT.
*/
private static void prt(String s) {
System.out.println(s);
}

private static void prt() {
System.out.println();
}

/**
* Calendar's getTime() method returns a Date object. This can then be
* passed to println() to print today's date (and time) in the traditional
* (but non-localized) format.
*/
private static void doCalendarTimeExample() {
prt("CURRENT DATE/TIME");
prt("=================================================================");
Date now = Calendar.getInstance().getTime();
prt(" Calendar.getInstance().getTime() : " + now);
prt();
}

/**
* Simple Date Format from java.text package.
*/
private static void doSimpleDateFormat() {
prt("SIMPLE DATE FORMAT");
prt("=================================================================");

// Get today's date
Calendar now = Calendar.getInstance();
SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");
prt(" It is now : " + formatter.format(now.getTime()));
prt();
}

/**
* Date Arithmetic function. Adds the specified (signed) amount of time to
* the given time field, based on the calendar's rules.
* The following examle:
* - Subtracts 2 years from the current time of the calendar
* - Adds 5 days from the current time of the calendar
*/
private static void doAdd() {

prt("ADD / SUBTRACT CALENDAR / DATEs");
prt("=================================================================");

// Get today's date
Calendar now = Calendar.getInstance();
Calendar working;
SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");

working = (Calendar) now.clone();
working.add(Calendar.DAY_OF_YEAR, - (365 * 2));
prt(" Two years ago it was: " + formatter.format(working.getTime()));

working = (Calendar) now.clone();
working.add(Calendar.DAY_OF_YEAR, + 5);
prt(" In five days it will be: " + formatter.format(working.getTime()));

prt();

}

private static void doDateDifference() {

prt("DIFFERENCE BETWEEN TWO DATES");
prt("=================================================================");
Date startDate1 = new GregorianCalendar(1994, 02, 14, 14, 00).getTime();
Date endDate1 = new Date();;

long diff = endDate1.getTime() - startDate1.getTime();

prt(" Difference between " + endDate1);
prt(" and " + startDate1 + " is " + (diff / (1000L*60L*60L*24L)) + " days.");
prt();

}

private static void doGetMethods() {

prt("CALENDAR GET METHODS");
prt("=================================================================");
Calendar c = Calendar.getInstance();

prt(" YEAR : " + c.get(Calendar.YEAR));
prt(" MONTH : " + c.get(Calendar.MONTH));
prt(" DAY_OF_MONTH : " + c.get(Calendar.DAY_OF_MONTH));
prt(" DAY_OF_WEEK : " + c.get(Calendar.DAY_OF_WEEK));
prt(" DAY_OF_YEAR : " + c.get(Calendar.DAY_OF_YEAR));
prt(" WEEK_OF_YEAR : " + c.get(Calendar.WEEK_OF_YEAR));
prt(" WEEK_OF_MONTH : " + c.get(Calendar.WEEK_OF_MONTH));
prt(" DAY_OF_WEEK_IN_MONTH : " + c.get(Calendar.DAY_OF_WEEK_IN_MONTH));
prt(" HOUR : " + c.get(Calendar.HOUR));
prt(" AM_PM : " + c.get(Calendar.AM_PM));
prt(" HOUR_OF_DAY (24-hour): " + c.get(Calendar.HOUR_OF_DAY));
prt(" MINUTE : " + c.get(Calendar.MINUTE));
prt(" SECOND : " + c.get(Calendar.SECOND));
prt();

}

public static void main(String[] args) {
prt();
doCalendarTimeExample();
doSimpleDateFormat();
doAdd();
doDateDifference();
doGetMethods();
}

}