On days that do have a leap second, the leap second is spread equally This is identical to UTC on days that do not have a leap second. In this segment, the Java Time-Scale is identical to There are currently, as of 2013, two segments in the Java time-scale.įor the segment from (exact boundary discussed below) untilįurther notice, the consensus international time scale is UTC (with the Java Time-Scale shall have a precisely-defined relationship to.the Java Time-Scale shall exactly match the international civil.the Java Time-Scale shall closely match the underlying international.Segment of the Java Time-Scale must be defined for it. Internationally-agreed time scale is modified or replaced, a new Time scale that is used as the basis for civil time. Segments of the time-line, each based on the consensus international The Java Time-Scale has slightly different definitions for different Scale, the definition of which changes from time to time. It closely matches the de facto international civil time The Java Time-Scale divides each calendar day into exactly 86400 Given the complexity of accurate timekeeping described above, this Java API defines To change the definition of UTC again, with the potential to remove leap seconds or The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds.īetween 19, the definition of UTC was complex, with minor sub-second leaps andĪlterations to the length of the notional second. Necessary in order to keep the day aligned with the Sun. Of a second from UT1 into whole seconds, known as leap-seconds.Ī leap-second may be added or removed depending on the Earth's rotational changes.Īs such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where The UTC time-scale is a standard approach to bundle up all the additional fractions The UT1 time-scale captures the accurate length of day, but is only available some The actual length of any given day and the amount by which the Earth is slowingĪre not predictable and can only be determined by measurement. In addition, over time the average length of the day is getting longer as the Earth slows.Īs a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds. Unfortunately, as the Earth rotates the length of the day varies. To be very close to the 86400th fraction of a day. Relative to the transitions of a Caesium atom. Modern timekeeping is based on atomic clocks which precisely define an SI second This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds, The length of the solar day is the standard way that humans measure time. Where instants after the epoch have positive values, and earlier instants have negative values.įor both the epoch-second and nanosecond parts, a larger value is always later on the time-line The epoch-seconds are measured from the standard Java epoch of Int representing nanosecond-of-second, which will always be between 0 and 999,999,999. To achieve this, the class stores a long representing epoch-seconds and an The range of an instant requires the storage of a number larger than a long. This might be used to record event time-stamps in the application. This class models a single instantaneous point on the time-line.
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