l.cam.ac.uk/~mgk25/time/utc-sls/">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 {@code 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 by all date-time classes. This includes {@code Instant}, {@code LocalDate}, {@code LocalTime}, {@code OffsetDateTime}, {@code ZonedDateTime} and {@code Duration}.
Specification for implementors
This class is immutable and thread-safe.