java7までの処理計測と、java8からの処理計測

TimeElapsed.java

import java.time.Duration;
import java.time.Instant;

public class DurationSample {

    public static void main(String[] args) {
        { // ~java1.7
            long start = System.nanoTime();
            someAlgorithm();
            long end = System.nanoTime();
            double elapse = (end - start) / 1000000.0;
            System.out.println(elapse + "[ms]");
        }
        { // java1.8~
            Instant start = Instant.now();
            someAlgorithm();
            Instant end = Instant.now();
            Duration elapse = Duration.between(start, end);
            System.out.println(elapse.toNanos() / 1000000.0 + "[ms]");
        }
    }

    private static void someAlgorithm() {
    	// some algorithm
    }
}