Instant (ThreeTen date and time API)

java.lang.Object
- javax.time.Instant

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Instant>, CalendricalAdjuster, CalendricalObject
```
public final class Instant
extends java.lang.Object
implements CalendricalObject, java.lang.Comparable<Instant>, java.io.Serializable
```
An instantaneous point on the time-line.
This class models a single instantaneous point on the time-line. This might be used to record event time-stamps in the application.
For practicality, the instant is stored with some constraints. The measurable time-line is restricted to the number of seconds that can be held in a long. This is greater than the current estimated age of the universe. The instant is stored to nanosecond resolution.
The range of an instant requires the storage of a number larger than a long. The standard storage scheme uses epoch-seconds measured from the standard Java epoch of 1970-01-01T00:00:00Z where instants after the epoch have positive values, and earlier instants have negative values. The standard storage stores the fraction of a second as nanosecond-of-second which will always be between 0 and 999,999,999.
Time-scale

The length of the solar day is the standard way that humans measure time. This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds, forming a 86400 second day.
Modern timekeeping is based on atomic clocks which precisely define an SI second relative to the transitions of a Caesium atom. The length of an SI second was defined to be very close to the 86400th fraction of a day.
Unfortunately, as the Earth rotates the length of the day varies. In addition, over time the average length of the day is getting longer as the Earth slows. As a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds. The actual length of any given day and the amount by which the Earth is slowing are not predictable and can only be determined by measurement. The UT1 time-scale captures the accurate length of day, but is only available some time after the day has completed.
The UTC time-scale is a standard approach to bundle up all the additional fractions of a second from UT1 into whole seconds, known as leap-seconds. A leap-second may be added or removed depending on the Earth's rotational changes. As such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where necessary in order to keep the day aligned with the Sun.
The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds. Between 1958 and 1972, the definition of UTC was complex, with minor sub-second leaps and alterations to the length of the notional second. As of 2012, discussions are underway to change the definition of UTC again, with the potential to remove leap seconds or introduce other changes.
Given the complexity of accurate timekeeping described above, this Java API defines its own time-scale with a simplification. The Java time-scale is defined as follows:
- midday will always be exactly as defined by the agreed international civil time
- other times during the day will be broadly in line with the agreed international civil time
- the day will be divided into exactly 86400 subdivisions, referred to as "seconds"
- the Java "second" may differ from an SI second
Agreed international civil time is the base time-scale agreed by international convention, which in 2012 is UTC (with leap-seconds).
In 2012, the definition of the Java time-scale is the same as UTC for all days except those where a leap-second occurs. On days where a leap-second does occur, the time-scale effectively eliminates the leap-second, maintaining the fiction of 86400 seconds in the day.
The main benefit of always dividing the day into 86400 subdivisions is that it matches the expectations of most users of the API. The alternative is to force every user to understand what a leap second is and to force them to have special logic to handle them. Most applications do not have access to a clock that is accurate enough to record leap-seconds. Most applications also do not have a problem with a second being a very small amount longer or shorter than a real SI second during a leap-second.
If an application does have access to an accurate clock that reports leap-seconds, then the recommended technique to implement the Java time-scale is to use the UTC-SLS convention. UTC-SLS effectively smoothes the leap-second over the last 1000 seconds of the day, making each of the last 1000 "seconds" 1/1000th longer or shorter than a real SI second.
One final problem is the definition of the agreed international civil time before the introduction of modern UTC in 1972. This includes the Java epoch of 1970-01-01. It is intended that instants before 1972 be interpreted based on the solar day divided into 86400 subdivisions.
The Java time-scale is used for all date-time classes supplied by JSR-310. This includes Instant, LocalDate, LocalTime, OffsetDateTime, ZonedDateTime and Duration.
Implementation notes
This class is immutable and thread-safe.
See Also:
Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

static Instant EPOCH
Constant for the 1970-01-01T00:00:00Z epoch instant.

Fields
Modifier and Type	Field and Description
`static Instant`	`EPOCH` Constant for the 1970-01-01T00:00:00Z epoch instant.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`compareTo(Instant otherInstant)` Compares this instant to the specified instant.
`boolean`	`equals(java.lang.Object otherInstant)` Checks if this instant is equal to the specified instant.
`<R> R`	`extract(java.lang.Class<R> type)` Extracts date-time information in a generic way.
`static Instant`	`from(CalendricalObject calendrical)` Obtains an instance of `Instant` from a calendrical.
`long`	`getEpochSecond()` Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.
`int`	`getNanoOfSecond()` Gets the number of nanoseconds, later along the time-line, from the start of the second.
`int`	`hashCode()` Returns a hash code for this instant.
`boolean`	`isAfter(Instant otherInstant)` Checks if this instant is after the specified instant.
`boolean`	`isBefore(Instant otherInstant)` Checks if this instant is before the specified instant.
`Instant`	`minus(Duration duration)` Returns a copy of this instant with the specified duration subtracted.
`Instant`	`minus(long amount, java.util.concurrent.TimeUnit unit)` Returns a copy of this duration with the specified duration subtracted.
`Instant`	`minusMillis(long millisToSubtract)` Returns a copy of this instant with the specified duration in milliseconds subtracted.
`Instant`	`minusNanos(long nanosToSubtract)` Returns a copy of this instant with the specified duration in nanoseconds subtracted.
`Instant`	`minusSeconds(long secondsToSubtract)` Returns a copy of this instant with the specified duration in seconds subtracted.
`static Instant`	`now()` Obtains the current instant from the system clock.
`static Instant`	`now(Clock clock)` Obtains the current instant from the specified clock.
`static Instant`	`ofEpochMilli(long epochMilli)` Obtains an instance of `Instant` using milliseconds from the epoch of 1970-01-01T00:00:00Z.
`static Instant`	`ofEpochNano(java.math.BigInteger epochNano)` Obtains an instance of `Instant` using nanoseconds from the epoch of 1970-01-01T00:00:00Z.
`static Instant`	`ofEpochNano(long epochNano)` Obtains an instance of `Instant` using nanoseconds from the epoch of 1970-01-01T00:00:00Z.
`static Instant`	`ofEpochSecond(java.math.BigDecimal epochSecond)` Obtains an instance of `Instant` using seconds from the epoch of 1970-01-01T00:00:00Z.
`static Instant`	`ofEpochSecond(long epochSecond)` Obtains an instance of `Instant` using seconds from the epoch of 1970-01-01T00:00:00Z.
`static Instant`	`ofEpochSecond(long epochSecond, long nanoAdjustment)` Obtains an instance of `Instant` using seconds from the epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.
`Instant`	`plus(Duration duration)` Returns a copy of this instant with the specified duration added.
`Instant`	`plus(long amount, java.util.concurrent.TimeUnit unit)` Returns a copy of this duration with the specified duration added.
`Instant`	`plusMillis(long millisToAdd)` Returns a copy of this instant with the specified duration in milliseconds added.
`Instant`	`plusNanos(long nanosToAdd)` Returns a copy of this instant with the specified duration in nanoseconds added.
`Instant`	`plusSeconds(long secondsToAdd)` Returns a copy of this instant with the specified duration in seconds added.
`long`	`toEpochMilli()` Converts this instant to the number of milliseconds from the epoch of 1970-01-01T00:00:00Z.
`java.math.BigInteger`	`toEpochNano()` Converts this instant to the number of nanoseconds from the epoch of 1970-01-01T00:00:00Z expressed as a `BigInteger`.
`java.math.BigDecimal`	`toEpochSecond()` Converts this instant to the number of seconds from the epoch of 1970-01-01T00:00:00Z expressed as a `BigDecimal`.
`java.lang.String`	`toString()` A string representation of this instant using ISO-8601 representation.
`Instant`	`with(CalendricalAdjuster adjuster)` Returns a copy of this calendrical with the specified calendrical set.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - EPOCH
```
public static final Instant EPOCH
```
    Constant for the 1970-01-01T00:00:00Z epoch instant.
- Method Detail
  - now
```
public static Instant now()
```
    Obtains the current instant from the system clock.
    This will query the system UTC clock to obtain the current instant.
    Using this method will prevent the ability to use an alternate time-source for testing because the clock is effectively hard-coded.
    
    Returns:
    the current instant using the system clock, not null
  - now
```
public static Instant now(Clock clock)
```
    Obtains the current instant from the specified clock.
    This will query the specified clock to obtain the current time.
    Using this method allows the use of an alternate clock for testing. The alternate clock may be introduced using dependency injection.
    
    Parameters:
    clock - the clock to use, not null
    
    Returns:
    the current instant, not null
  - ofEpochSecond
```
public static Instant ofEpochSecond(long epochSecond)
```
    Obtains an instance of Instant using seconds from the epoch of 1970-01-01T00:00:00Z.
    The nanosecond field is set to zero.
    
    Parameters:
    epochSecond - the number of seconds from 1970-01-01T00:00:00Z
    
    Returns:
    an instant, not null
  - ofEpochSecond
```
public static Instant ofEpochSecond(long epochSecond,
                    long nanoAdjustment)
```
    Obtains an instance of Instant using seconds from the epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.
    This method allows an arbitrary number of nanoseconds to be passed in. The factory will alter the values of the second and nanosecond in order to ensure that the stored nanosecond is in the range 0 to 999,999,999. For example, the following will result in the exactly the same instant:
```
  Instant.ofSeconds(3, 1);
  Instant.ofSeconds(4, -999999999);
  Instant.ofSeconds(2, 1000000001);
 
```
    Parameters:
    epochSecond - the number of seconds from 1970-01-01T00:00:00Z
    nanoAdjustment - the nanosecond adjustment to the number of seconds, positive or negative
    
    Returns:
    an instant, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - ofEpochSecond
```
public static Instant ofEpochSecond(java.math.BigDecimal epochSecond)
```
    Obtains an instance of Instant using seconds from the epoch of 1970-01-01T00:00:00Z.
    The seconds and nanoseconds are extracted from the specified BigDecimal. If the decimal is larger than Long.MAX_VALUE or has more than 9 decimal places then an exception is thrown.
    
    Parameters:
    epochSecond - the number of seconds from 1970-01-01T00:00:00Z, up to scale 9
    
    Returns:
    an instant, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - ofEpochMilli
```
public static Instant ofEpochMilli(long epochMilli)
```
    Obtains an instance of Instant using milliseconds from the epoch of 1970-01-01T00:00:00Z.
    The seconds and nanoseconds are extracted from the specified milliseconds.
    
    Parameters:
    epochMilli - the number of milliseconds from 1970-01-01T00:00:00Z
    
    Returns:
    an instant, not null
  - ofEpochNano
```
public static Instant ofEpochNano(long epochNano)
```
    Obtains an instance of Instant using nanoseconds from the epoch of 1970-01-01T00:00:00Z.
    The seconds and nanoseconds are extracted from the specified nanoseconds.
    
    Parameters:
    epochNano - the number of nanoseconds from 1970-01-01T00:00:00Z
    
    Returns:
    an instant, not null
  - ofEpochNano
```
public static Instant ofEpochNano(java.math.BigInteger epochNano)
```
    Obtains an instance of Instant using nanoseconds from the epoch of 1970-01-01T00:00:00Z.
    The seconds and nanoseconds are extracted from the specified BigInteger. If the resulting seconds value is larger than Long.MAX_VALUE then an exception is thrown.
    
    Parameters:
    epochNano - the number of nanoseconds from 1970-01-01T00:00:00Z, not null
    
    Returns:
    an instant, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - from
```
public static Instant from(CalendricalObject calendrical)
```
    Obtains an instance of Instant from a calendrical.
    A calendrical represents some form of date and time information. This factory converts the arbitrary calendrical to an instance of Instant.
    
    Parameters:
    calendrical - the calendrical to convert, not null
    
    Returns:
    the instant, not null
    
    Throws:
    
    CalendricalException - if unable to convert to an Instant
  - getEpochSecond
```
public long getEpochSecond()
```
    Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.
    The epoch second count is a simple incrementing count of seconds where second 0 is 1970-01-01T00:00:00Z. The nanosecond part of the day is returned by getNanosOfSecond.
    
    Returns:
    the seconds from the epoch of 1970-01-01T00:00:00Z
  - getNanoOfSecond
```
public int getNanoOfSecond()
```
    Gets the number of nanoseconds, later along the time-line, from the start of the second.
    The nanosecond-of-second value measures the total number of nanoseconds from the second returned by getEpochSecond.
    
    Returns:
    the nanoseconds within the second, always positive, never exceeds 999,999,999
  - plus
```
public Instant plus(Duration duration)
```
    Returns a copy of this instant with the specified duration added.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    duration - the duration to add, positive or negative, not null
    
    Returns:
    an Instant based on this instant with the specified duration added, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - plus
```
public Instant plus(long amount,
           java.util.concurrent.TimeUnit unit)
```
    Returns a copy of this duration with the specified duration added.
    The duration to be added is measured in terms of the specified unit.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    amount - the duration to add, positive or negative
    unit - the unit that the duration is measured in, not null
    
    Returns:
    an Instant based on this duration with the specified duration added, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - plusSeconds
```
public Instant plusSeconds(long secondsToAdd)
```
    Returns a copy of this instant with the specified duration in seconds added.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    secondsToAdd - the seconds to add, positive or negative
    
    Returns:
    an Instant based on this instant with the specified seconds added, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - plusMillis
```
public Instant plusMillis(long millisToAdd)
```
    Returns a copy of this instant with the specified duration in milliseconds added.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    millisToAdd - the milliseconds to add, positive or negative
    
    Returns:
    an Instant based on this instant with the specified milliseconds added, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - plusNanos
```
public Instant plusNanos(long nanosToAdd)
```
    Returns a copy of this instant with the specified duration in nanoseconds added.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    nanosToAdd - the nanoseconds to add, positive or negative
    
    Returns:
    an Instant based on this instant with the specified nanoseconds added, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - minus
```
public Instant minus(Duration duration)
```
    Returns a copy of this instant with the specified duration subtracted.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    duration - the duration to subtract, positive or negative, not null
    
    Returns:
    an Instant based on this instant with the specified duration subtracted, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - minus
```
public Instant minus(long amount,
            java.util.concurrent.TimeUnit unit)
```
    Returns a copy of this duration with the specified duration subtracted.
    The duration to be subtracted is measured in terms of the specified unit.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    amount - the duration to subtract, positive or negative
    unit - the unit that the duration is measured in, not null
    
    Returns:
    a Duration based on this duration with the specified duration subtracted, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - minusSeconds
```
public Instant minusSeconds(long secondsToSubtract)
```
    Returns a copy of this instant with the specified duration in seconds subtracted.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    secondsToSubtract - the seconds to subtract, positive or negative
    
    Returns:
    an Instant based on this instant with the specified seconds subtracted, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - minusMillis
```
public Instant minusMillis(long millisToSubtract)
```
    Returns a copy of this instant with the specified duration in milliseconds subtracted.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    millisToSubtract - the milliseconds to subtract, positive or negative
    
    Returns:
    an Instant based on this instant with the specified milliseconds subtracted, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - minusNanos
```
public Instant minusNanos(long nanosToSubtract)
```
    Returns a copy of this instant with the specified duration in nanoseconds subtracted.
    This instance is immutable and unaffected by this method call.
    
    Parameters:
    nanosToSubtract - the nanoseconds to subtract, positive or negative
    
    Returns:
    an Instant based on this instant with the specified nanoseconds subtracted, not null
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - extract
```
public <R> R extract(java.lang.Class<R> type)
```
    Extracts date-time information in a generic way.
    This method exists to fulfill the CalendricalObject interface. This implementation returns the following types:
    - Instant
    - DateTimeBuilder
    - Class, returning Instant
    Specified by:
    
    extract in interface CalendricalObject
    
    Type Parameters:
    R - the type to extract
    Parameters:
    type - the type to extract, null returns null
    
    Returns:
    the extracted object, null if unable to extract
  - with
```
public Instant with(CalendricalAdjuster adjuster)
```
    Description copied from interface: CalendricalObject
    Returns a copy of this calendrical with the specified calendrical set.
    This allows the manipulation of a calendrical in a general way. For example, if this calendrical is a LocalDateTime and the specified calendrical is a LocalDate, then the implementation will return a new LocalDateTime with the date changed.
    An implementation must handle the following types if possible:
    - DateAdjuster
    - TimeAdjuster
    - LocalDate
    - LocalTime
    - LocalDateTime
    - OffsetDate
    - OffsetTime
    - OffsetDateTime
    - ZoneOffset
    - ZoneId
    - Instant
    - this object if the specified type is passed in
    Specified by:
    
    with in interface CalendricalObject
    
    Parameters:
    adjuster - the calendrical to set into this calendrical, null returns null
    
    Returns:
    a copy of this calendrical with the specified calendrical set, not null
  - toEpochSecond
```
public java.math.BigDecimal toEpochSecond()
```
    Converts this instant to the number of seconds from the epoch of 1970-01-01T00:00:00Z expressed as a BigDecimal.
    
    Returns:
    the number of seconds since the epoch of 1970-01-01T00:00:00Z, scale 9, not null
  - toEpochNano
```
public java.math.BigInteger toEpochNano()
```
    Converts this instant to the number of nanoseconds from the epoch of 1970-01-01T00:00:00Z expressed as a BigInteger.
    
    Returns:
    the number of nanoseconds since the epoch of 1970-01-01T00:00:00Z, not null
  - toEpochMilli
```
public long toEpochMilli()
```
    Converts this instant to the number of milliseconds from the epoch of 1970-01-01T00:00:00Z.
    If this instant represents a point on the time-line too far in the future or past to fit in a long milliseconds, then an exception is thrown.
    If this instant has greater than millisecond precision, then the conversion will drop any excess precision information as though the amount in nanoseconds was subject to integer division by one million.
    
    Returns:
    the number of milliseconds since the epoch of 1970-01-01T00:00:00Z
    
    Throws:
    
    java.lang.ArithmeticException - if the calculation exceeds the supported range
  - compareTo
```
public int compareTo(Instant otherInstant)
```
    Compares this instant to the specified instant.
    The comparison is based on the time-line position of the instants.
    
    Specified by:
    
    compareTo in interface java.lang.Comparable<Instant>
    
    Parameters:
    otherInstant - the other instant to compare to, not null
    
    Returns:
    the comparator value, negative if less, positive if greater
    
    Throws:
    
    java.lang.NullPointerException - if otherInstant is null
  - isAfter
```
public boolean isAfter(Instant otherInstant)
```
    Checks if this instant is after the specified instant.
    The comparison is based on the time-line position of the instants.
    
    Parameters:
    otherInstant - the other instant to compare to, not null
    
    Returns:
    true if this instant is after the specified instant
    
    Throws:
    
    java.lang.NullPointerException - if otherInstant is null
  - isBefore
```
public boolean isBefore(Instant otherInstant)
```
    Checks if this instant is before the specified instant.
    The comparison is based on the time-line position of the instants.
    
    Parameters:
    otherInstant - the other instant to compare to, not null
    
    Returns:
    true if this instant is before the specified instant
    
    Throws:
    
    java.lang.NullPointerException - if otherInstant is null
  - equals
```
public boolean equals(java.lang.Object otherInstant)
```
    Checks if this instant is equal to the specified instant.
    The comparison is based on the time-line position of the instants.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    otherInstant - the other instant, null returns false
    
    Returns:
    true if the other instant is equal to this one
  - hashCode
```
public int hashCode()
```
    Returns a hash code for this instant.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    a suitable hash code
  - toString
```
public java.lang.String toString()
```
    A string representation of this instant using ISO-8601 representation.
    The format of the returned string will be yyyy-MM-ddTHH:mm:ss.SSSSSSSSSZ.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    an ISO-8601 representation of this instant, not null

Class Instant

Time-scale

Implementation notes

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EPOCH

Method Detail

now

now

ofEpochSecond

ofEpochSecond

ofEpochSecond

ofEpochMilli

ofEpochNano

ofEpochNano

from

getEpochSecond

getNanoOfSecond

plus

plus

plusSeconds

plusMillis

plusNanos

minus

minus

minusSeconds

minusMillis

minusNanos

extract

with

toEpochSecond

toEpochNano

toEpochMilli

compareTo

isAfter

isBefore

equals

hashCode

toString