ofEpochSecondlong

ofEpochSecond(long) is a static factory method in the Java.time API, most commonly associated with the java.time.Instant class. It creates an Instant representing a moment in UTC that is a specified number of seconds from the epoch, which is defined as 1970-01-01T00:00:00Z. The resulting Instant has its nanosecond component set to zero, meaning it represents whole-second precision.

The method accepts a single parameter of type long, representing the epoch second count. The value can be positive or negative, allowing times after or before the epoch. If the provided epoch second is outside the supported range for Instant, the method may throw a DateTimeException, signaling that the requested moment cannot be represented by the time API.

There is also an overload, ofEpochSecond(long epochSecond, long nanoAdjustment), which adds a nanosecond adjustment to the base epoch second. This enables creation of instants with sub-second precision by supplying a nanoAdjustment value that can be positive or negative. The resulting Instant corresponds to epochSecond seconds plus the specified nanoseconds, and is still interpreted as a moment in UTC.

Usage of ofEpochSecond is common when converting Unix timestamps or external time data into the Java time model, enabling consistent handling and formatting across the Java time API. It is part of a family of factory methods that includes ofEpochMilli and related constructors, all designed to bridge epoch-based time representations with the language’s temporal objects.