How to convert java nanoseconds to seconds using the TimeUnit enum? Ask Question

391 Asked by BrianKennedy in Java , Asked on Jun 21, 2021

How to convert a value from nanoseconds to seconds?

Here's the code segment:

import java.io.*;
import java.util.concurrent.*; 
..
class Stamper { 
public static void main (String[] args) { 
long start = System.nanoTime(); 
//some try with nested loops 
long end = System.nanoTime(); 
long elapsedTime = end - start;
System.out.println("elapsed: " + elapsedTime + "nano secondsn");
//convert to seconds 
TimeUnit seconds = new TimeUnit(); 
System.out.println("which is " + seconds.toSeconds(elapsedTime) + " seconds"); 
}}

The error is

Stamper.java:16:  enum types may not be instantiated.

What does this mean?

Answered by Dan Peters

Well, you could just divide by 1,000,000,000:

long elapsedTime = end - start;

double seconds = (double)elapsedTime / 1_000_000_000.0;

If you use TimeUnit to convert, you'll get your result as a long, so you'll lose decimal precision but maintain whole number precision.

How to convert java nanoseconds to seconds using the TimeUnit enum? Ask Question

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