How to get decimal result when converting nanosecond to millisecond?

Question

Using TimeUnit, how can I convert 665477 nanosecond to 0.665477 millisecond?

long t = TimeUnit.MILLISECONDS.convert(665477L, TimeUnit.NANOSECONDS);

This always gives 0 but I need decimal points precision.

Answer 1

shorter and less error prone:

double millis = 665477 / 1E6;

milli -> mikro -> nano

are two steps, each step has a conversion faktor of 1000 = 1E3; So makes one million, which can easier be read as 1E6, than by counting zeros.

Answer 2

From Java Documentation - TimeUnit#convert

public long convert(long sourceDuration,TimeUnit sourceUnit)

Convert the given time duration in the given unit to this unit. Conversions from finer to coarser granularities truncate, so lose precision. For example converting 999 milliseconds to seconds results in 0. Conversions from coarser to finer granularities with arguments that would numerically overflow saturate to Long.MIN_VALUE if negative or Long.MAX_VALUE if positive.

So to get your answer

double milliseconds = 665477 / 1000000.0;