Java GregorianCalendar Initialize
September 23, 2021
GregorianCalendar.
1. The
java.util.GregorianCalendar is the subclass of java.util.Calendar abstract class.
2. The
GregorianCalendar provides the standard calendar system.
3. The
GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems.
Here on this page, we will learn the ways to initialize the
GregorianCalendar. The GregorianCalendar has different constructors to initialize it. Let discuss them one-by-one.
Contents
Constructor with No Arguments
GregorianCalendar()
GregorianCalendar using the current time in the default time zone with default FORMAT locale.
Example:
Calendar c = new GregorianCalendar(); System.out.println(c.getTime());
Wed Sep 22 18:37:20 IST 2021
Using Date Sets
Find the constructors with date sets.GregorianCalendar(int year, int month, int dayOfMonth) GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute) GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute, int second)
month: Sets MONTH calendar field. It starts with 0 and that is January.
dayOfMonth: Sets DAY_OF_MONTH calendar field.
hourOfDay: Sets HOUR_OF_DAY calendar field.
minute: Sets MINUTE calendar field.
second: Sets SECOND calendar field.
Example:
Calendar c1 = new GregorianCalendar(2021, 8, 22); // 8 is for September System.out.println(c1.getTime()); Calendar c2 = new GregorianCalendar(2021, 8, 22, 10, 7); System.out.println(c2.getTime()); Calendar c3 = new GregorianCalendar(2021, 8, 22, 10, 7, 50); System.out.println(c3.getTime());
Wed Sep 22 00:00:00 IST 2021 Wed Sep 22 10:07:00 IST 2021 Wed Sep 22 10:07:50 IST 2021
Using Locale
GregorianCalendar(Locale aLocale)
GregorianCalendar based on the current time in the default time zone with the given locale.
Example:
Calendar c = new GregorianCalendar(Locale.FRANCE); System.out.println(c.getTime());
Thu Sep 23 08:54:52 IST 2021
Using TimeZone
GregorianCalendar(TimeZone zone)
GregorianCalendar based on the current time in the given time zone with the default FORMAT locale.
Example:
TimeZone t = SimpleTimeZone.getTimeZone("Asia/Calcutta");
Calendar c = new GregorianCalendar(t);
System.out.println(c.getTime());
Thu Sep 23 09:19:08 IST 2021
Using TimeZone and Locale
GregorianCalendar(TimeZone zone, Locale aLocale)
GregorianCalendar based on the current time in the given time zone with the given locale.
Example:
TimeZone t = SimpleTimeZone.getTimeZone("Europe/Paris");
Calendar c = new GregorianCalendar(t, Locale.FRANCE);
System.out.println(c.getTime());
Thu Sep 23 09:24:32 IST 2021
From ZonedDateTime
Find the staticfrom method of GregorianCalendar.
static GregorianCalendar from(ZonedDateTime zdt)
GregorianCalendar with the default locale from a ZonedDateTime object.
2. Since
ZonedDateTime uses ISO calendar system and does not support a Julian-Gregorian cutover date, the instance of GregorianCalendar obtained from from method, is a pure Gregorian calendar and uses ISO 8601 standard for week definitions.
3. It has MONDAY as the
FirstDayOfWeek and 4 as the value of the MinimalDaysInFirstWeek.
4. If the zoned date-time is too large to represent as a
GregorianCalendar, it will throw IllegalArgumentException.
Example:
ZonedDateTime zdt = ZonedDateTime.now(); GregorianCalendar gc = GregorianCalendar.from(zdt); System.out.println(gc.getTime());
Thu Sep 23 18:17:20 IST 2021
Default Fields Values
TheCalendar.clear() method sets all calendar field values and time values of this calendar undefined. The GregorianCalendar uses default values for some of those fields that are as following.
ERA = AD YEAR = 1970 MONTH = JANUARY DAY_OF_MONTH = 1 DAY_OF_WEEK = the first day of week WEEK_OF_MONTH = 0 DAY_OF_WEEK_IN_MONTH = 1 AM_PM = AM HOUR, HOUR_OF_DAY, MINUTE, SECOND, MILLISECOND = 0
GregorianCalendar does not provide default values for other fields which are not listed above.
Example:
Calendar c = new GregorianCalendar(); System.out.println(c.getTime()); c.clear(); System.out.println(c.getTime());
Wed Sep 22 19:54:47 IST 2021 Thu Jan 01 00:00:00 IST 1970
