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The main API for dates, times, instants, and durations.
The classes defined here represent the principal date-time concepts,
including instants, durations, dates, times, time-zones and periods.
They are based on the ISO calendar system, which is the de facto world
calendar following the proleptic Gregorian rules.
All the classes are immutable and thread-safe.
Each date time instance is composed of fields that are conveniently
made available by the APIs. For lower level access to the fields refer
to the {@link java.bp.temporal} package.
Each class includes support for printing and parsing all manner of dates and times.
Refer to the {@link java.bp.format} package for customization options.
The {@link java.bp.chrono} package contains the calendar neutral API.
This is intended for use by applications that need to use localized calendars.
It is recommended that applications use the ISO-8601 dates and time classes from
this package across system boundaries, such as to the database or across the network.
The calendar neutral API should be reserved for interactions with users.
Dates and Times
{@link java.bp.Instant} is essentially a numeric timestamp.
The current Instant can be retrieved from a {@link java.bp.Clock}.
This is useful for logging and persistence of a point in time
and has in the past been associated with storing the result
from {@link java.lang.System#currentTimeMillis()}.
{@link java.bp.LocalDate} stores a date without a time.
This stores a date like '2010-12-03' and could be used to store a birthday.
{@link java.bp.LocalTime} stores a time without a date.
This stores a time like '11:30' and could be used to store an opening or closing time.
{@link java.bp.LocalDateTime} stores a date and time.
This stores a date-time like '2010-12-03T11:30'.
{@link java.bp.OffsetTime} stores a time and offset from UTC without a date.
This stores a date like '11:30+01:00'.
The {@link java.bp.ZoneOffset ZoneOffset} is of the form '+01:00'.
{@link java.bp.OffsetDateTime} stores a date and time and offset from UTC.
This stores a date-time like '2010-12-03T11:30+01:00'.
This is sometimes found in XML messages and other forms of persistence,
but contains less information than a full time-zone.
{@link java.bp.ZonedDateTime} stores a date and time with a time-zone.
This is useful if you want to perform accurate calculations of
dates and times taking into account the {@link java.bp.ZoneId}, such as 'Europe/Paris'.
Where possible, it is recommended to use a simpler class.
The widespread use of time-zones tends to add considerable complexity to an application.
Duration and Period
Beyond dates and times, the API also allows the storage of period and durations of time.
A {@link java.bp.Duration} is a simple measure of time along the time-line in nanoseconds.
A {@link java.bp.Period} expresses an amount of time in units meaningful to humans, such as years or hours.
Additional value types
{@link java.bp.Year} stores a year on its own.
This stores a single year in isolation, such as '2010'.
{@link java.bp.YearMonth} stores a year and month without a day or time.
This stores a year and month, such as '2010-12' and could be used for a credit card expiry.
{@link java.bp.MonthDay} stores a month and day without a year or time.
This stores a month and day-of-month, such as '--12-03' and
could be used to store an annual event like a birthday without storing the year.
{@link java.bp.Month} stores a month on its own.
This stores a single month-of-year in isolation, such as 'DECEMBER'.
{@link java.bp.DayOfWeek} stores a day-of-week on its own.
This stores a single day-of-week in isolation, such as 'TUESDAY'.