How do I create Java Instant from epoch microseconds or nanoseconds?

Question

I'm trying to standardize time stamp format for my project, where the source reports in microsecond precision. I'm trying to find out whether there is a clean or minimal approach that does not require using handwritten constants.

Answer 1

Thanks for the suggestions. This is the cleanest I could come up with:

static Instant getInstantFromMicros(long microsSinceEpoch) {
    return Instant.ofEpochSecond(
            TimeUnit.MICROSECONDS.toSeconds(microsSinceEpoch), 
            TimeUnit.MICROSECONDS.toNanos(
                    Math.floorMod(microsSinceEpoch, TimeUnit.SECONDS.toMicros(1))
            )
    );
}

static Instant getInstantFromNanos(long nanosSinceEpoch) {
    return Instant.ofEpochSecond(0L, nanosSinceEpoch);
}

Test Cases:

System.out.println(getInstantFromMicros(1_500_000_000_123_456L));
// 2017-07-14T02:40:00.123456Z
    
System.out.println(getInstantFromNanos(1_500_000_000_123_456_789L));
// 2017-07-14T02:40:00.123456789Z