Added in API level 1

GregorianCalendar

public class GregorianCalendar
extends Calendar

java.lang.Object
↳	java.util.Calendar
	↳	java.util.GregorianCalendar

GregorianCalendar is a concrete subclass of Calendar and provides the standard calendar system used by most of the world.

GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems with the support of a single discontinuity, which corresponds by default to the Gregorian date when the Gregorian calendar was instituted (October 15, 1582 in some countries, later in others). The cutover date may be changed by the caller by calling setGregorianChange().

Historically, in those countries which adopted the Gregorian calendar first, October 4, 1582 (Julian) was thus followed by October 15, 1582 (Gregorian). This calendar models this correctly. Before the Gregorian cutover, GregorianCalendar implements the Julian calendar. The only difference between the Gregorian and the Julian calendar is the leap year rule. The Julian calendar specifies leap years every four years, whereas the Gregorian calendar omits century years which are not divisible by 400.

GregorianCalendar implements proleptic Gregorian and Julian calendars. That is, dates are computed by extrapolating the current rules indefinitely far backward and forward in time. As a result, GregorianCalendar may be used for all years to generate meaningful and consistent results. However, dates obtained using GregorianCalendar are historically accurate only from March 1, 4 AD onward, when modern Julian calendar rules were adopted. Before this date, leap year rules were applied irregularly, and before 45 BC the Julian calendar did not even exist.

Prior to the institution of the Gregorian calendar, New Year's Day was March 25. To avoid confusion, this calendar always uses January 1. A manual adjustment may be made if desired for dates that are prior to the Gregorian changeover and which fall between January 1 and March 24.

Week Of Year and Week Year

Values calculated for the WEEK_OF_YEAR field range from 1 to 53. The first week of a calendar year is the earliest seven day period starting on getFirstDayOfWeek() that contains at least getMinimalDaysInFirstWeek() days from that year. It thus depends on the values of getMinimalDaysInFirstWeek(), getFirstDayOfWeek(), and the day of the week of January 1. Weeks between week 1 of one year and week 1 of the following year (exclusive) are numbered sequentially from 2 to 52 or 53 (except for year(s) involved in the Julian-Gregorian transition).

The getFirstDayOfWeek() and getMinimalDaysInFirstWeek() values are initialized using locale-dependent resources when constructing a GregorianCalendar. The week determination is compatible with the ISO 8601 standard when getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4, which values are used in locales where the standard is preferred. These values can explicitly be set by calling setFirstDayOfWeek() and setMinimalDaysInFirstWeek().

A week year is in sync with a WEEK_OF_YEAR cycle. All weeks between the first and last weeks (inclusive) have the same week year value. Therefore, the first and last days of a week year may have different calendar year values.

For example, January 1, 1998 is a Thursday. If getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4 (ISO 8601 standard compatible setting), then week 1 of 1998 starts on December 29, 1997, and ends on January 4, 1998. The week year is 1998 for the last three days of calendar year 1997. If, however, getFirstDayOfWeek() is SUNDAY, then week 1 of 1998 starts on January 4, 1998, and ends on January 10, 1998; the first three days of 1998 then are part of week 53 of 1997 and their week year is 1997.

Week Of Month

Values calculated for the WEEK_OF_MONTH field range from 0 to 6. Week 1 of a month (the days with WEEK_OF_MONTH = 1) is the earliest set of at least getMinimalDaysInFirstWeek() contiguous days in that month, ending on the day before getFirstDayOfWeek(). Unlike week 1 of a year, week 1 of a month may be shorter than 7 days, need not start on getFirstDayOfWeek(), and will not include days of the previous month. Days of a month before week 1 have a WEEK_OF_MONTH of 0.

For example, if getFirstDayOfWeek() is SUNDAY and getMinimalDaysInFirstWeek() is 4, then the first week of January 1998 is Sunday, January 4 through Saturday, January 10. These days have a WEEK_OF_MONTH of 1. Thursday, January 1 through Saturday, January 3 have a WEEK_OF_MONTH of 0. If getMinimalDaysInFirstWeek() is changed to 3, then January 1 through January 3 have a WEEK_OF_MONTH of 1.

Default Fields Values

The clear method sets calendar field(s) undefined. GregorianCalendar uses the following default value for each calendar field if its value is undefined.

GregorianCalendar default field values
Field	Default Value
`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`

Default values are not applicable for the fields not listed above.

Example:

 // get the supported ids for GMT-08:00 (Pacific Standard Time)
 String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);
 // if no ids were returned, something is wrong. get out.
 if (ids.length == 0)
     System.exit(0);

  // begin output
 System.out.println("Current Time");

 // create a Pacific Standard Time time zone
 SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);

 // set up rules for Daylight Saving Time
 pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
 pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);

 // create a GregorianCalendar with the Pacific Daylight time zone
 // and the current date and time
 Calendar calendar = new GregorianCalendar(pdt);
 Date trialTime = new Date();
 calendar.setTime(trialTime);

 // print out a bunch of interesting things
 System.out.println("ERA: " + calendar.get(Calendar.ERA));
 System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 System.out.println("DATE: " + calendar.get(Calendar.DATE));
 System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 System.out.println("DAY_OF_WEEK_IN_MONTH: "
                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 System.out.println("ZONE_OFFSET: "
                    + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
 System.out.println("DST_OFFSET: "
                    + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));
 System.out.println("Current Time, with hour reset to 3");
 calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
 calendar.set(Calendar.HOUR, 3);
 System.out.println("ERA: " + calendar.get(Calendar.ERA));
 System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 System.out.println("DATE: " + calendar.get(Calendar.DATE));
 System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 System.out.println("DAY_OF_WEEK_IN_MONTH: "
                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 System.out.println("ZONE_OFFSET: "
        + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
 System.out.println("DST_OFFSET: "
        + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours

See also:

TimeZone

Summary

Constants
`int`	`AD` Value of the `ERA` field indicating the common era (Anno Domini), also known as CE.
`int`	`BC` Value of the `ERA` field indicating the period before the common era (before Christ), also known as BCE.

Inherited constants

From class java.util.Calendar

`int`	`ALL_STYLES` A style specifier for `getDisplayNames` indicating names in all styles, such as "January" and "Jan".
`int`	`AM` Value of the `AM_PM` field indicating the period of the day from midnight to just before noon.
`int`	`AM_PM` Field number for `get` and `set` indicating whether the `HOUR` is before or after noon.
`int`	`APRIL` Value of the `MONTH` field indicating the fourth month of the year in the Gregorian and Julian calendars.
`int`	`AUGUST` Value of the `MONTH` field indicating the eighth month of the year in the Gregorian and Julian calendars.
`int`	`DATE` Field number for `get` and `set` indicating the day of the month.
`int`	`DAY_OF_MONTH` Field number for `get` and `set` indicating the day of the month.
`int`	`DAY_OF_WEEK` Field number for `get` and `set` indicating the day of the week.
`int`	`DAY_OF_WEEK_IN_MONTH` Field number for `get` and `set` indicating the ordinal number of the day of the week within the current month.
`int`	`DAY_OF_YEAR` Field number for `get` and `set` indicating the day number within the current year.
`int`	`DECEMBER` Value of the `MONTH` field indicating the twelfth month of the year in the Gregorian and Julian calendars.
`int`	`DST_OFFSET` Field number for `get` and `set` indicating the daylight saving offset in milliseconds.
`int`	`ERA` Field number for `get` and `set` indicating the era, e.g., AD or BC in the Julian calendar.
`int`	`FEBRUARY` Value of the `MONTH` field indicating the second month of the year in the Gregorian and Julian calendars.
`int`	`FIELD_COUNT` The number of distinct fields recognized by `get` and `set`.
`int`	`FRIDAY` Value of the `DAY_OF_WEEK` field indicating Friday.
`int`	`HOUR` Field number for `get` and `set` indicating the hour of the morning or afternoon.
`int`	`HOUR_OF_DAY` Field number for `get` and `set` indicating the hour of the day.
`int`	`JANUARY` Value of the `MONTH` field indicating the first month of the year in the Gregorian and Julian calendars.
`int`	`JULY` Value of the `MONTH` field indicating the seventh month of the year in the Gregorian and Julian calendars.
`int`	`JUNE` Value of the `MONTH` field indicating the sixth month of the year in the Gregorian and Julian calendars.
`int`	`LONG` A style specifier for `getDisplayName` and `getDisplayNames` equivalent to `LONG_FORMAT`.
`int`	`LONG_FORMAT` A style specifier for `getDisplayName` and `getDisplayNames` indicating a long name used for format.
`int`	`LONG_STANDALONE` A style specifier for `getDisplayName` and `getDisplayNames` indicating a long name used independently, such as a month name as calendar headers.
`int`	`MARCH` Value of the `MONTH` field indicating the third month of the year in the Gregorian and Julian calendars.
`int`	`MAY` Value of the `MONTH` field indicating the fifth month of the year in the Gregorian and Julian calendars.
`int`	`MILLISECOND` Field number for `get` and `set` indicating the millisecond within the second.
`int`	`MINUTE` Field number for `get` and `set` indicating the minute within the hour.
`int`	`MONDAY` Value of the `DAY_OF_WEEK` field indicating Monday.
`int`	`MONTH` Field number for `get` and `set` indicating the month.
`int`	`NARROW_FORMAT` A style specifier for `getDisplayName` and `getDisplayNames` indicating a narrow name used for format.
`int`	`NARROW_STANDALONE` A style specifier for `getDisplayName` and `getDisplayNames` indicating a narrow name independently.
`int`	`NOVEMBER` Value of the `MONTH` field indicating the eleventh month of the year in the Gregorian and Julian calendars.
`int`	`OCTOBER` Value of the `MONTH` field indicating the tenth month of the year in the Gregorian and Julian calendars.
`int`	`PM` Value of the `AM_PM` field indicating the period of the day from noon to just before midnight.
`int`	`SATURDAY` Value of the `DAY_OF_WEEK` field indicating Saturday.
`int`	`SECOND` Field number for `get` and `set` indicating the second within the minute.
`int`	`SEPTEMBER` Value of the `MONTH` field indicating the ninth month of the year in the Gregorian and Julian calendars.
`int`	`SHORT` A style specifier for `getDisplayName` and `getDisplayNames` equivalent to `SHORT_FORMAT`.
`int`	`SHORT_FORMAT` A style specifier for `getDisplayName` and `getDisplayNames` indicating a short name used for format.
`int`	`SHORT_STANDALONE` A style specifier for `getDisplayName` and `getDisplayNames` indicating a short name used independently, such as a month abbreviation as calendar headers.
`int`	`SUNDAY` Value of the `DAY_OF_WEEK` field indicating Sunday.
`int`	`THURSDAY` Value of the `DAY_OF_WEEK` field indicating Thursday.
`int`	`TUESDAY` Value of the `DAY_OF_WEEK` field indicating Tuesday.
`int`	`UNDECIMBER` Value of the `MONTH` field indicating the thirteenth month of the year.
`int`	`WEDNESDAY` Value of the `DAY_OF_WEEK` field indicating Wednesday.
`int`	`WEEK_OF_MONTH` Field number for `get` and `set` indicating the week number within the current month.
`int`	`WEEK_OF_YEAR` Field number for `get` and `set` indicating the week number within the current year.
`int`	`YEAR` Field number for `get` and `set` indicating the year.
`int`	`ZONE_OFFSET` Field number for `get` and `set` indicating the raw offset from GMT in milliseconds.

Inherited fields

From class java.util.Calendar

`protected boolean`	`areFieldsSet` True if `fields[]` are in sync with the currently set time.
`protected int[]`	`fields` The calendar field values for the currently set time for this calendar.
`protected boolean[]`	`isSet` The flags which tell if a specified calendar field for the calendar is set.
`protected boolean`	`isTimeSet` True if then the value of `time` is valid.
`protected long`	`time` The currently set time for this calendar, expressed in milliseconds after January 1, 1970, 0:00:00 GMT.

Public constructors
`GregorianCalendar()` Constructs a default `GregorianCalendar` using the current time in the default time zone with the default `FORMAT` locale.
`GregorianCalendar(TimeZone zone)` Constructs a `GregorianCalendar` based on the current time in the given time zone with the default `FORMAT` locale.
`GregorianCalendar(Locale aLocale)` Constructs a `GregorianCalendar` based on the current time in the default time zone with the given locale.
`GregorianCalendar(TimeZone zone, Locale aLocale)` Constructs a `GregorianCalendar` based on the current time in the given time zone with the given locale.
`GregorianCalendar(int year, int month, int dayOfMonth)` Constructs a `GregorianCalendar` with the given date set in the default time zone with the default locale.
`GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute)` Constructs a `GregorianCalendar` with the given date and time set for the default time zone with the default locale.
`GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute, int second)` Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.

Public methods
`void`	`add(int field, int amount)` Adds the specified (signed) amount of time to the given calendar field, based on the calendar's rules.
`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Compares this `GregorianCalendar` to the specified `Object`.
`static GregorianCalendar`	`from(ZonedDateTime zdt)` Obtains an instance of `GregorianCalendar` with the default locale from a `ZonedDateTime` object.
`int`	`getActualMaximum(int field)` Returns the maximum value that this calendar field could have, taking into consideration the given time value and the current values of the `getFirstDayOfWeek`, `getMinimalDaysInFirstWeek`, `getGregorianChange` and `getTimeZone` methods.
`int`	`getActualMinimum(int field)` Returns the minimum value that this calendar field could have, taking into consideration the given time value and the current values of the `getFirstDayOfWeek`, `getMinimalDaysInFirstWeek`, `getGregorianChange` and `getTimeZone` methods.
`String`	`getCalendarType()` Returns `"gregory"` as the calendar type.
`int`	`getGreatestMinimum(int field)` Returns the highest minimum value for the given calendar field of this `GregorianCalendar` instance.
`final Date`	`getGregorianChange()` Gets the Gregorian Calendar change date.
`int`	`getLeastMaximum(int field)` Returns the lowest maximum value for the given calendar field of this `GregorianCalendar` instance.
`int`	`getMaximum(int field)` Returns the maximum value for the given calendar field of this `GregorianCalendar` instance.
`int`	`getMinimum(int field)` Returns the minimum value for the given calendar field of this `GregorianCalendar` instance.
`TimeZone`	`getTimeZone()` Gets the time zone.
`int`	`getWeekYear()` Returns the week year represented by this `GregorianCalendar`.
`int`	`getWeeksInWeekYear()` Returns the number of weeks in the week year represented by this `GregorianCalendar`.
`int`	`hashCode()` Generates the hash code for this `GregorianCalendar` object.
`boolean`	`isLeapYear(int year)` Determines if the given year is a leap year.
`final boolean`	`isWeekDateSupported()` Returns `true` indicating this `GregorianCalendar` supports week dates.
`void`	`roll(int field, boolean up)` Adds or subtracts (up/down) a single unit of time on the given time field without changing larger fields.
`void`	`roll(int field, int amount)` Adds a signed amount to the specified calendar field without changing larger fields.
`void`	`setGregorianChange(Date date)` Sets the `GregorianCalendar` change date.
`void`	`setTimeZone(TimeZone zone)` Sets the time zone with the given time zone value.
`void`	`setWeekDate(int weekYear, int weekOfYear, int dayOfWeek)` Sets this `GregorianCalendar` to the date given by the date specifiers - `weekYear`, `weekOfYear`, and `dayOfWeek`.
`ZonedDateTime`	`toZonedDateTime()` Converts this object to a `ZonedDateTime` that represents the same point on the time-line as this `GregorianCalendar`.

Protected methods
`void`	`computeFields()` Converts the time value (millisecond offset from the Epoch) to calendar field values.
`void`	`computeTime()` Converts calendar field values to the time value (millisecond offset from the Epoch).

Inherited methods

From class


        
          java.util.Calendar

`abstract void`	`add(int field, int amount)` Adds or subtracts the specified amount of time to the given calendar field, based on the calendar's rules.
`boolean`	`after(Object when)` Returns whether this `Calendar` represents a time after the time represented by the specified `Object`.
`boolean`	`before(Object when)` Returns whether this `Calendar` represents a time before the time represented by the specified `Object`.
`final void`	`clear()` Sets all the calendar field values and the time value (millisecond offset from the Epoch) of this `Calendar` undefined.
`final void`	`clear(int field)` Sets the given calendar field value and the time value (millisecond offset from the Epoch) of this `Calendar` undefined.
`Object`	`clone()` Creates and returns a copy of this object.
`int`	`compareTo(Calendar anotherCalendar)` Compares the time values (millisecond offsets from the Epoch) represented by two `Calendar` objects.
`void`	`complete()` Fills in any unset fields in the calendar fields.
`abstract void`	`computeFields()` Converts the current millisecond time value `time` to calendar field values in `fields[]`.
`abstract void`	`computeTime()` Converts the current calendar field values in `fields[]` to the millisecond time value `time`.
`boolean`	`equals(Object obj)` Compares this `Calendar` to the specified `Object`.
`int`	`get(int field)` Returns the value of the given calendar field.
`int`	`getActualMaximum(int field)` Returns the maximum value that the specified calendar field could have, given the time value of this `Calendar`.
`int`	`getActualMinimum(int field)` Returns the minimum value that the specified calendar field could have, given the time value of this `Calendar`.
`static Set<String>`	`getAvailableCalendarTypes()` Returns an unmodifiable `Set` containing all calendar types supported by `Calendar` in the runtime environment.
`static Locale[]`	`getAvailableLocales()` Returns an array of all locales for which the `getInstance` methods of this class can return localized instances.
`String`	`getCalendarType()` Returns the calendar type of this `Calendar`.
`String`	`getDisplayName(int field, int style, Locale locale)` Returns the string representation of the calendar `field` value in the given `style` and `locale`.
`Map<String, Integer>`	`getDisplayNames(int field, int style, Locale locale)` Returns a `Map` containing all names of the calendar `field` in the given `style` and `locale` and their corresponding field values.
`int`	`getFirstDayOfWeek()` Gets what the first day of the week is; e.g., `SUNDAY` in the U.S., `MONDAY` in France.
`abstract int`	`getGreatestMinimum(int field)` Returns the highest minimum value for the given calendar field of this `Calendar` instance.
`static Calendar`	`getInstance()` Gets a calendar using the default time zone and locale.
`static Calendar`	`getInstance(Locale aLocale)` Gets a calendar using the default time zone and specified locale.
`static Calendar`	`getInstance(TimeZone zone, Locale aLocale)` Gets a calendar with the specified time zone and locale.
`static Calendar`	`getInstance(TimeZone zone)` Gets a calendar using the specified time zone and default locale.
`abstract int`	`getLeastMaximum(int field)` Returns the lowest maximum value for the given calendar field of this `Calendar` instance.
`abstract int`	`getMaximum(int field)` Returns the maximum value for the given calendar field of this `Calendar` instance.
`int`	`getMinimalDaysInFirstWeek()` Gets what the minimal days required in the first week of the year are; e.g., if the first week is defined as one that contains the first day of the first month of a year, this method returns 1.
`abstract int`	`getMinimum(int field)` Returns the minimum value for the given calendar field of this `Calendar` instance.
`final Date`	`getTime()` Returns a `Date` object representing this `Calendar`'s time value (millisecond offset from the Epoch").
`long`	`getTimeInMillis()` Returns this Calendar's time value in milliseconds.
`TimeZone`	`getTimeZone()` Gets the time zone.
`int`	`getWeekYear()` Returns the week year represented by this `Calendar`.
`int`	`getWeeksInWeekYear()` Returns the number of weeks in the week year represented by this `Calendar`.
`int`	`hashCode()` Returns a hash code for this calendar.
`final int`	`internalGet(int field)` Returns the value of the given calendar field.
`boolean`	`isLenient()` Tells whether date/time interpretation is to be lenient.
`final boolean`	`isSet(int field)` Determines if the given calendar field has a value set, including cases that the value has been set by internal fields calculations triggered by a `get` method call.
`boolean`	`isWeekDateSupported()` Returns whether this `Calendar` supports week dates.
`abstract void`	`roll(int field, boolean up)` Adds or subtracts (up/down) a single unit of time on the given time field without changing larger fields.
`void`	`roll(int field, int amount)` Adds the specified (signed) amount to the specified calendar field without changing larger fields.
`final void`	`set(int year, int month, int date, int hourOfDay, int minute, int second)` Sets the values for the fields `YEAR`, `MONTH`, `DAY_OF_MONTH`, `HOUR_OF_DAY`, `MINUTE`, and `SECOND`.
`final void`	`set(int year, int month, int date, int hourOfDay, int minute)` Sets the values for the calendar fields `YEAR`, `MONTH`, `DAY_OF_MONTH`, `HOUR_OF_DAY`, and `MINUTE`.
`void`	`set(int field, int value)` Sets the given calendar field to the given value.
`final void`	`set(int year, int month, int date)` Sets the values for the calendar fields `YEAR`, `MONTH`, and `DAY_OF_MONTH`.
`void`	`setFirstDayOfWeek(int value)` Sets what the first day of the week is; e.g., `SUNDAY` in the U.S., `MONDAY` in France.
`void`	`setLenient(boolean lenient)` Specifies whether or not date/time interpretation is to be lenient.
`void`	`setMinimalDaysInFirstWeek(int value)` Sets what the minimal days required in the first week of the year are; For example, if the first week is defined as one that contains the first day of the first month of a year, call this method with value 1.
`final void`	`setTime(Date date)` Sets this Calendar's time with the given `Date`.
`void`	`setTimeInMillis(long millis)` Sets this Calendar's current time from the given long value.
`void`	`setTimeZone(TimeZone value)` Sets the time zone with the given time zone value.
`void`	`setWeekDate(int weekYear, int weekOfYear, int dayOfWeek)` Sets the date of this `Calendar` with the given date specifiers - week year, week of year, and day of week.
`final Instant`	`toInstant()` Converts this object to an `Instant`.
`String`	`toString()` Return a string representation of this calendar.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.lang.Comparable


      compareTo(Calendar o)

Compares this object with the specified object for order.

Constants

Added in API level 1

public static final int AD

Value of the ERA field indicating the common era (Anno Domini), also known as CE. The sequence of years at the transition from BC to AD is ..., 2 BC, 1 BC, 1 AD, 2 AD,...

See also:

Calendar.ERA

Constant Value: 1 (0x00000001)

BC

Added in API level 1

public static final int BC

Value of the ERA field indicating the period before the common era (before Christ), also known as BCE. The sequence of years at the transition from BC to AD is ..., 2 BC, 1 BC, 1 AD, 2 AD,...

See also:

Calendar.ERA

Constant Value: 0 (0x00000000)

Public constructors

GregorianCalendar

Added in API level 1

public GregorianCalendar ()

Constructs a default GregorianCalendar using the current time in the default time zone with the default FORMAT locale.

GregorianCalendar

Added in API level 1

public GregorianCalendar (TimeZone zone)

Constructs a GregorianCalendar based on the current time in the given time zone with the default FORMAT locale.

Parameters
`zone`	`TimeZone`: the given time zone.

GregorianCalendar

Added in API level 1

public GregorianCalendar (Locale aLocale)

Constructs a GregorianCalendar based on the current time in the default time zone with the given locale.

Parameters
`aLocale`	`Locale`: the given locale.

GregorianCalendar

Added in API level 1

public GregorianCalendar (TimeZone zone, 
                Locale aLocale)

Constructs a GregorianCalendar based on the current time in the given time zone with the given locale.

Parameters
`zone`	`TimeZone`: the given time zone.
`aLocale`	`Locale`: the given locale.

GregorianCalendar

Added in API level 1

public GregorianCalendar (int year, 
                int month, 
                int dayOfMonth)

Constructs a GregorianCalendar with the given date set in the default time zone with the default locale.

Parameters
`year`	`int`: the value used to set the `YEAR` calendar field in the calendar.
`month`	`int`: the value used to set the `MONTH` calendar field in the calendar. Month value is 0-based. e.g., 0 for January.
`dayOfMonth`	`int`: the value used to set the `DAY_OF_MONTH` calendar field in the calendar.

GregorianCalendar

Added in API level 1

public GregorianCalendar (int year, 
                int month, 
                int dayOfMonth, 
                int hourOfDay, 
                int minute)

Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.

Parameters
`year`	`int`: the value used to set the `YEAR` calendar field in the calendar.
`month`	`int`: the value used to set the `MONTH` calendar field in the calendar. Month value is 0-based. e.g., 0 for January.
`dayOfMonth`	`int`: the value used to set the `DAY_OF_MONTH` calendar field in the calendar.
`hourOfDay`	`int`: the value used to set the `HOUR_OF_DAY` calendar field in the calendar.
`minute`	`int`: the value used to set the `MINUTE` calendar field in the calendar.

GregorianCalendar

Added in API level 1

public GregorianCalendar (int year, 
                int month, 
                int dayOfMonth, 
                int hourOfDay, 
                int minute, 
                int second)

Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.

Parameters
`year`	`int`: the value used to set the `YEAR` calendar field in the calendar.
`month`	`int`: the value used to set the `MONTH` calendar field in the calendar. Month value is 0-based. e.g., 0 for January.
`dayOfMonth`	`int`: the value used to set the `DAY_OF_MONTH` calendar field in the calendar.
`hourOfDay`	`int`: the value used to set the `HOUR_OF_DAY` calendar field in the calendar.
`minute`	`int`: the value used to set the `MINUTE` calendar field in the calendar.
`second`	`int`: the value used to set the `SECOND` calendar field in the calendar.

Public methods

add

Added in API level 1

public void add (int field, 
                int amount)

Adds the specified (signed) amount of time to the given calendar field, based on the calendar's rules.

Add rule 1. The value of field after the call minus the value of field before the call is amount, modulo any overflow that has occurred in field. Overflow occurs when a field value exceeds its range and, as a result, the next larger field is incremented or decremented and the field value is adjusted back into its range.

Add rule 2. If a smaller field is expected to be invariant, but it is impossible for it to be equal to its prior value because of changes in its minimum or maximum after field is changed, then its value is adjusted to be as close as possible to its expected value. A smaller field represents a smaller unit of time. HOUR is a smaller field than DAY_OF_MONTH. No adjustment is made to smaller fields that are not expected to be invariant. The calendar system determines what fields are expected to be invariant.

Parameters
`field`	`int`: the calendar field.
`amount`	`int`: the amount of date or time to be added to the field.

Throws
`IllegalArgumentException`	if `field` is `ZONE_OFFSET`, `DST_OFFSET`, or unknown, or if any calendar fields have out-of-range values in non-lenient mode.

clone

Added in API level 1

public Object clone ()

Creates and returns a copy of this object.

Returns
`Object`	a copy of this object.

equals

Added in API level 1

public boolean equals (Object obj)

Compares this GregorianCalendar to the specified Object. The result is true if and only if the argument is a GregorianCalendar object that represents the same time value (millisecond offset from the Epoch) under the same Calendar parameters and Gregorian change date as this object.

Parameters
`obj`	`Object`: the object to compare with.

Returns
`boolean`	`true` if this object is equal to `obj`; `false` otherwise.

See also:

Calendar.compareTo(Calendar)

from

Added in API level 26

public static GregorianCalendar from (ZonedDateTime zdt)

Obtains an instance of GregorianCalendar with the default locale from a ZonedDateTime object.

Since ZonedDateTime does not support a Julian-Gregorian cutover date and uses ISO calendar system, the return GregorianCalendar is a pure Gregorian calendar and uses ISO 8601 standard for week definitions, which has MONDAY as the FirstDayOfWeek and 4 as the value of the MinimalDaysInFirstWeek.

ZoneDateTime can store points on the time-line further in the future and further in the past than GregorianCalendar. In this scenario, this method will throw an IllegalArgumentException exception.

Parameters
`zdt`	`ZonedDateTime`: the zoned date-time object to convert

Returns
`GregorianCalendar`	the gregorian calendar representing the same point on the time-line as the zoned date-time provided

Throws
`NullPointerException`	if `zdt` is null
`IllegalArgumentException`	if the zoned date-time is too large to represent as a `GregorianCalendar`

getActualMaximum

Added in API level 1

public int getActualMaximum (int field)

Returns the maximum value that this calendar field could have, taking into consideration the given time value and the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods. For example, if the date of this instance is February 1, 2004, the actual maximum value of the DAY_OF_MONTH field is 29 because 2004 is a leap year, and if the date of this instance is February 1, 2005, it's 28.

This method calculates the maximum value of WEEK_OF_YEAR based on the YEAR (calendar year) value, not the week year. Call getWeeksInWeekYear() to get the maximum value of WEEK_OF_YEAR in the week year of this GregorianCalendar.

Parameters
`field`	`int`: the calendar field

Returns
`int`	the maximum of the given field for the time value of this `GregorianCalendar`

See also:

getActualMinimum

Added in API level 1

public int getActualMinimum (int field)

Returns the minimum value that this calendar field could have, taking into consideration the given time value and the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods.

For example, if the Gregorian change date is January 10, 1970 and the date of this GregorianCalendar is January 20, 1970, the actual minimum value of the DAY_OF_MONTH field is 10 because the previous date of January 10, 1970 is December 27, 1996 (in the Julian calendar). Therefore, December 28, 1969 to January 9, 1970 don't exist.

Parameters
`field`	`int`: the calendar field

Returns
`int`	the minimum of the given field for the time value of this `GregorianCalendar`

See also:

getCalendarType

Added in API level 26

public String getCalendarType ()

Returns "gregory" as the calendar type.

Returns
`String`	`"gregory"`

getGreatestMinimum

Added in API level 1

public int getGreatestMinimum (int field)

Returns the highest minimum value for the given calendar field of this GregorianCalendar instance. The highest minimum value is defined as the largest value returned by getActualMinimum(int) for any possible time value, taking into consideration the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods.

Parameters
`field`	`int`: the calendar field.

Returns
`int`	the highest minimum value for the given calendar field.

See also:

getGregorianChange

Added in API level 1

public final Date getGregorianChange ()

Gets the Gregorian Calendar change date. This is the point when the switch from Julian dates to Gregorian dates occurred. Default is October 15, 1582 (Gregorian). Previous to this, dates will be in the Julian calendar.

Returns
`Date`	the Gregorian cutover date for this `GregorianCalendar` object.

getLeastMaximum

Added in API level 1

public int getLeastMaximum (int field)

Returns the lowest maximum value for the given calendar field of this GregorianCalendar instance. The lowest maximum value is defined as the smallest value returned by getActualMaximum(int) for any possible time value, taking into consideration the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods.

Parameters
`field`	`int`: the calendar field

Returns
`int`	the lowest maximum value for the given calendar field.

See also:

getMaximum

Added in API level 1

public int getMaximum (int field)

Returns the maximum value for the given calendar field of this GregorianCalendar instance. The maximum value is defined as the largest value returned by the get method for any possible time value, taking into consideration the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods.

Parameters
`field`	`int`: the calendar field.

Returns
`int`	the maximum value for the given calendar field.

See also:

getMinimum

Added in API level 1

public int getMinimum (int field)

Returns the minimum value for the given calendar field of this GregorianCalendar instance. The minimum value is defined as the smallest value returned by the get method for any possible time value, taking into consideration the current values of the getFirstDayOfWeek, getMinimalDaysInFirstWeek, getGregorianChange and getTimeZone methods.

Parameters
`field`	`int`: the calendar field.

Returns
`int`	the minimum value for the given calendar field.

See also:

getTimeZone

Added in API level 1

public TimeZone getTimeZone ()

Gets the time zone.

Returns
`TimeZone`	the time zone object associated with this calendar.

getWeekYear

Added in API level 24

public int getWeekYear ()

Returns the week year represented by this GregorianCalendar. The dates in the weeks between 1 and the maximum week number of the week year have the same week year value that may be one year before or after the YEAR (calendar year) value.

This method calls Calendar#complete() before calculating the week year.

Returns
`int`	the week year represented by this `GregorianCalendar`. If the `ERA` value is `BC`, the year is represented by 0 or a negative number: BC 1 is 0, BC 2 is -1, BC 3 is -2, and so on.

Throws
`IllegalArgumentException`	if any of the calendar fields is invalid in non-lenient mode.

See also:

getWeeksInWeekYear

Added in API level 24

public int getWeeksInWeekYear ()

Returns the number of weeks in the week year represented by this GregorianCalendar.

For example, if this GregorianCalendar's date is December 31, 2008 with the ISO 8601 compatible setting, this method will return 53 for the period: December 29, 2008 to January 3, 2010 while getActualMaximum(WEEK_OF_YEAR) will return 52 for the period: December 31, 2007 to December 28, 2008.

Returns
`int`	the number of weeks in the week year.

See also:

hashCode

Added in API level 1

public int hashCode ()

Generates the hash code for this GregorianCalendar object.

Returns
`int`	a hash code value for this object.

isLeapYear

Added in API level 1

public boolean isLeapYear (int year)

Determines if the given year is a leap year. Returns true if the given year is a leap year. To specify BC year numbers, 1 - year number must be given. For example, year BC 4 is specified as -3.

Parameters
`year`	`int`: the given year.

Returns
`boolean`	`true` if the given year is a leap year; `false` otherwise.

isWeekDateSupported

Added in API level 24

public final boolean isWeekDateSupported ()

Returns true indicating this GregorianCalendar supports week dates.

Returns
`boolean`	`true` (always)

See also:

roll

Added in API level 1

public void roll (int field, 
                boolean up)

Adds or subtracts (up/down) a single unit of time on the given time field without changing larger fields.

Example: Consider a GregorianCalendar originally set to December 31, 1999. Calling roll(Calendar.MONTH, true) sets the calendar to January 31, 1999. The YEAR field is unchanged because it is a larger field than MONTH.

Parameters
`field`	`int`: the time field.
`up`	`boolean`: indicates if the value of the specified calendar field is to be rolled up or rolled down. Use `true` if rolling up, `false` otherwise.

Throws
`IllegalArgumentException`	if `field` is `ZONE_OFFSET`, `DST_OFFSET`, or unknown, or if any calendar fields have out-of-range values in non-lenient mode.

See also:

roll

Added in API level 1

public void roll (int field, 
                int amount)

Adds a signed amount to the specified calendar field without changing larger fields. A negative roll amount means to subtract from field without changing larger fields. If the specified amount is 0, this method performs nothing.

This method calls Calendar.complete() before adding the amount so that all the calendar fields are normalized. If there is any calendar field having an out-of-range value in non-lenient mode, then an IllegalArgumentException is thrown.

Example: Consider a GregorianCalendar originally set to August 31, 1999. Calling roll(Calendar.MONTH, 8) sets the calendar to April 30, 1999. Using a GregorianCalendar, the DAY_OF_MONTH field cannot be 31 in the month April. DAY_OF_MONTH is set to the closest possible value, 30. The YEAR field maintains the value of 1999 because it is a larger field than MONTH.

Example: Consider a GregorianCalendar originally set to Sunday June 6, 1999. Calling roll(Calendar.WEEK_OF_MONTH, -1) sets the calendar to Tuesday June 1, 1999, whereas calling add(Calendar.WEEK_OF_MONTH, -1) sets the calendar to Sunday May 30, 1999. This is because the roll rule imposes an additional constraint: The MONTH must not change when the WEEK_OF_MONTH is rolled. Taken together with add rule 1, the resultant date must be between Tuesday June 1 and Saturday June 5. According to add rule 2, the DAY_OF_WEEK, an invariant when changing the WEEK_OF_MONTH, is set to Tuesday, the closest possible value to Sunday (where Sunday is the first day of the week).

Parameters
`field`	`int`: the calendar field.
`amount`	`int`: the signed amount to add to `field`.

Throws
`IllegalArgumentException`	if `field` is `ZONE_OFFSET`, `DST_OFFSET`, or unknown, or if any calendar fields have out-of-range values in non-lenient mode.

See also:

setGregorianChange

Added in API level 1

public void setGregorianChange (Date date)

Sets the GregorianCalendar change date. This is the point when the switch from Julian dates to Gregorian dates occurred. Default is October 15, 1582 (Gregorian). Previous to this, dates will be in the Julian calendar.

To obtain a pure Julian calendar, set the change date to Date(Long.MAX_VALUE). To obtain a pure Gregorian calendar, set the change date to Date(Long.MIN_VALUE).

Parameters
`date`	`Date`: the given Gregorian cutover date.

setTimeZone

Added in API level 1

public void setTimeZone (TimeZone zone)

Sets the time zone with the given time zone value.

Parameters
`zone`	`TimeZone`: the given time zone.

setWeekDate

Added in API level 24

public void setWeekDate (int weekYear, 
                int weekOfYear, 
                int dayOfWeek)

Sets this GregorianCalendar to the date given by the date specifiers - weekYear, weekOfYear, and dayOfWeek. weekOfYear follows the WEEK_OF_YEAR numbering. The dayOfWeek value must be one of the DAY_OF_WEEK values: SUNDAY to SATURDAY.

Note that the numeric day-of-week representation differs from the ISO 8601 standard, and that the weekOfYear numbering is compatible with the standard when getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4.

Unlike the set method, all of the calendar fields and the instant of time value are calculated upon return.

If weekOfYear is out of the valid week-of-year range in weekYear, the weekYear and weekOfYear values are adjusted in lenient mode, or an IllegalArgumentException is thrown in non-lenient mode.

Parameters
`weekYear`	`int`: the week year
`weekOfYear`	`int`: the week number based on `weekYear`
`dayOfWeek`	`int`: the day of week value: one of the constants for the `DAY_OF_WEEK` field: `SUNDAY`, ..., `SATURDAY`.

Throws
`IllegalArgumentException`	if any of the given date specifiers is invalid, or if any of the calendar fields are inconsistent with the given date specifiers in non-lenient mode

See also:

toZonedDateTime

Added in API level 26

public ZonedDateTime toZonedDateTime ()

Converts this object to a ZonedDateTime that represents the same point on the time-line as this GregorianCalendar.

Since this object supports a Julian-Gregorian cutover date and ZonedDateTime does not, it is possible that the resulting year, month and day will have different values. The result will represent the correct date in the ISO calendar system, which will also be the same value for Modified Julian Days.

Returns
`ZonedDateTime`	a zoned date-time representing the same point on the time-line as this gregorian calendar

Protected methods

computeFields

Added in API level 1

protected void computeFields ()

Converts the time value (millisecond offset from the Epoch) to calendar field values. The time is not recomputed first; to recompute the time, then the fields, call the complete method.

See also:

Calendar.complete()

computeTime

Added in API level 1

protected void computeTime ()

Converts calendar field values to the time value (millisecond offset from the Epoch).

Throws
`IllegalArgumentException`	if any calendar fields are invalid.