# java.time.chrono Added in[API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) # java.time.chrono Generic API for calendar systems other than the default ISO. The main API is based around the calendar system defined in ISO-8601. However, there are other calendar systems, and this package provides basic support for them. The alternate calendars are provided in the[java.time.chrono](https://developer.android.com/reference/java/time/chrono/package-summary)package. A calendar system is defined by the[Chronology](https://developer.android.com/reference/java/time/chrono/Chronology)interface, while a date in a calendar system is defined by the[ChronoLocalDate](https://developer.android.com/reference/java/time/chrono/ChronoLocalDate)interface. It is intended that applications use the main API whenever possible, including code to read and write from a persistent data store, such as a database, and to send dates and times across a network. The "chrono" classes are then used at the user interface level to deal with localized input/output. See[ChronoLocalDate](https://developer.android.com/reference/java/time/chrono/ChronoLocalDate)for a full discussion of the issues. Using non-ISO calendar systems in an application introduces significant extra complexity. Ensure that the warnings and recommendations in`ChronoLocalDate`have been read before working with the "chrono" interfaces. The supported calendar systems includes: - [Hijrah calendar](https://developer.android.com/reference/java/time/chrono/HijrahChronology) - [Japanese calendar](https://developer.android.com/reference/java/time/chrono/JapaneseChronology) - [Minguo calendar](https://developer.android.com/reference/java/time/chrono/MinguoChronology) - [Thai Buddhist calendar](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistChronology) ## Example This example lists today's date for all of the available calendars. ``` // Enumerate the list of available calendars and print today's date for each. Set chronos = Chronology.getAvailableChronologies(); for (Chronology chrono : chronos) { ChronoLocalDate date = chrono.dateNow(); System.out.printf(" %20s: %s%n", chrono.getId(), date.toString()); } ``` This example creates and uses a date in a named non-ISO calendar system. ``` // Print the Thai Buddhist date ChronoLocalDate now1 = Chronology.of("ThaiBuddhist").dateNow(); int day = now1.get(ChronoField.DAY_OF_MONTH); int dow = now1.get(ChronoField.DAY_OF_WEEK); int month = now1.get(ChronoField.MONTH_OF_YEAR); int year = now1.get(ChronoField.YEAR); System.out.printf(" Today is %s %s %d-%s-%d%n", now1.getChronology().getId(), dow, day, month, year); // Print today's date and the last day of the year for the Thai Buddhist Calendar. ChronoLocalDate first = now1 .with(ChronoField.DAY_OF_MONTH, 1) .with(ChronoField.MONTH_OF_YEAR, 1); ChronoLocalDate last = first .plus(1, ChronoUnit.YEARS) .minus(1, ChronoUnit.DAYS); System.out.printf(" %s: 1st of year: %s; end of year: %s%n", last.getChronology().getId(), first, last); ``` This example creates and uses a date in a specific ThaiBuddhist calendar system. ``` // Print the Thai Buddhist date ThaiBuddhistDate now1 = ThaiBuddhistDate.now(); int day = now1.get(ChronoField.DAY_OF_MONTH); int dow = now1.get(ChronoField.DAY_OF_WEEK); int month = now1.get(ChronoField.MONTH_OF_YEAR); int year = now1.get(ChronoField.YEAR); System.out.printf(" Today is %s %s %d-%s-%d%n", now1.getChronology().getId(), dow, day, month, year); // Print today's date and the last day of the year for the Thai Buddhist Calendar. ThaiBuddhistDate first = now1 .with(ChronoField.DAY_OF_MONTH, 1) .with(ChronoField.MONTH_OF_YEAR, 1); ThaiBuddhistDate last = first .plus(1, ChronoUnit.YEARS) .minus(1, ChronoUnit.DAYS); System.out.printf(" %s: 1st of year: %s; end of year: %s%n", last.getChronology().getId(), first, last); ``` ## Package specification Unless otherwise noted, passing a null argument to a constructor or method in any class or interface in this package will cause a[NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException)to be thrown. The Javadoc "@param" definition is used to summarise the null-behavior. The "@throws[NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException)" is not explicitly documented in each method. All calculations should check for numeric overflow and throw either an[ArithmeticException](https://developer.android.com/reference/java/lang/ArithmeticException)or a[DateTimeException](https://developer.android.com/reference/java/time/DateTimeException). ## Interfaces |-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------| | [ChronoLocalDate](https://developer.android.com/reference/java/time/chrono/ChronoLocalDate) | A date without time-of-day or time-zone in an arbitrary chronology, intended for advanced globalization use cases. | | [ChronoLocalDateTime](https://developer.android.com/reference/java/time/chrono/ChronoLocalDateTime)\ | A date-time without a time-zone in an arbitrary chronology, intended for advanced globalization use cases. | | [Chronology](https://developer.android.com/reference/java/time/chrono/Chronology) | A calendar system, used to organize and identify dates. | | [ChronoPeriod](https://developer.android.com/reference/java/time/chrono/ChronoPeriod) | A date-based amount of time, such as '3 years, 4 months and 5 days' in an arbitrary chronology, intended for advanced globalization use cases. | | [ChronoZonedDateTime](https://developer.android.com/reference/java/time/chrono/ChronoZonedDateTime)\ | A date-time with a time-zone in an arbitrary chronology, intended for advanced globalization use cases. | | [Era](https://developer.android.com/reference/java/time/chrono/Era) | An era of the time-line. | ## Classes |-----------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------| | [AbstractChronology](https://developer.android.com/reference/java/time/chrono/AbstractChronology) | An abstract implementation of a calendar system, used to organize and identify dates. | | [HijrahChronology](https://developer.android.com/reference/java/time/chrono/HijrahChronology) | The Hijrah calendar is a lunar calendar supporting Islamic calendars. | | [HijrahDate](https://developer.android.com/reference/java/time/chrono/HijrahDate) | A date in the Hijrah calendar system. | | [IsoChronology](https://developer.android.com/reference/java/time/chrono/IsoChronology) | The ISO calendar system. | | [JapaneseChronology](https://developer.android.com/reference/java/time/chrono/JapaneseChronology) | The Japanese Imperial calendar system. | | [JapaneseDate](https://developer.android.com/reference/java/time/chrono/JapaneseDate) | A date in the Japanese Imperial calendar system. | | [JapaneseEra](https://developer.android.com/reference/java/time/chrono/JapaneseEra) | An era in the Japanese Imperial calendar system. | | [MinguoChronology](https://developer.android.com/reference/java/time/chrono/MinguoChronology) | The Minguo calendar system. | | [MinguoDate](https://developer.android.com/reference/java/time/chrono/MinguoDate) | A date in the Minguo calendar system. | | [ThaiBuddhistChronology](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistChronology) | The Thai Buddhist calendar system. | | [ThaiBuddhistDate](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistDate) | A date in the Thai Buddhist calendar system. | ## Enums |---------------------------------------------------------------------------------------------|----------------------------------------------| | [HijrahEra](https://developer.android.com/reference/java/time/chrono/HijrahEra) | An era in the Hijrah calendar system. | | [IsoEra](https://developer.android.com/reference/java/time/chrono/IsoEra) | An era in the ISO calendar system. | | [MinguoEra](https://developer.android.com/reference/java/time/chrono/MinguoEra) | An era in the Minguo calendar system. | | [ThaiBuddhistEra](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistEra) | An era in the Thai Buddhist calendar system. | - ## Interfaces - [ChronoLocalDate](https://developer.android.com/reference/java/time/chrono/ChronoLocalDate) - [ChronoLocalDateTime](https://developer.android.com/reference/java/time/chrono/ChronoLocalDateTime) - [Chronology](https://developer.android.com/reference/java/time/chrono/Chronology) - [ChronoPeriod](https://developer.android.com/reference/java/time/chrono/ChronoPeriod) - [ChronoZonedDateTime](https://developer.android.com/reference/java/time/chrono/ChronoZonedDateTime) - [Era](https://developer.android.com/reference/java/time/chrono/Era) - ## Classes - [AbstractChronology](https://developer.android.com/reference/java/time/chrono/AbstractChronology) - [HijrahChronology](https://developer.android.com/reference/java/time/chrono/HijrahChronology) - [HijrahDate](https://developer.android.com/reference/java/time/chrono/HijrahDate) - [IsoChronology](https://developer.android.com/reference/java/time/chrono/IsoChronology) - [JapaneseChronology](https://developer.android.com/reference/java/time/chrono/JapaneseChronology) - [JapaneseDate](https://developer.android.com/reference/java/time/chrono/JapaneseDate) - [JapaneseEra](https://developer.android.com/reference/java/time/chrono/JapaneseEra) - [MinguoChronology](https://developer.android.com/reference/java/time/chrono/MinguoChronology) - [MinguoDate](https://developer.android.com/reference/java/time/chrono/MinguoDate) - [ThaiBuddhistChronology](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistChronology) - [ThaiBuddhistDate](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistDate) - ## Enums - [HijrahEra](https://developer.android.com/reference/java/time/chrono/HijrahEra) - [IsoEra](https://developer.android.com/reference/java/time/chrono/IsoEra) - [MinguoEra](https://developer.android.com/reference/java/time/chrono/MinguoEra) - [ThaiBuddhistEra](https://developer.android.com/reference/java/time/chrono/ThaiBuddhistEra)