How do I calculate process execution time in higher resolution?

This example demonstrates how to use the System.nanoTime() method to calculate processing execution time in higher resolution. The processing time calculated in nanoseconds resolution.

package org.kodejava.example.lang;

public class NanoSecondsTimerResolution {
    public static void main(String[] args) {
        // Get process execution start time in nanoseconds.
        long start = System.nanoTime();
        System.out.println("Process start... " + start);

        try {
            Thread.sleep(5000); // Simulate a long process.
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        // Get process execution finish time in nanoseconds.
        long finish = System.nanoTime();
        System.out.println("Process finish... " + finish);

        // Calculate the process execution time.
        long execTime = finish - start;
        System.out.println("Processing time = " + execTime + "(ns)");
    }
}

How do I calculate process elapsed time?

This example shows us how to use the System.nanoTime() method to get the amount of time a process take place. Please be aware that the nano time value is not related to the real world time value.

package org.kodejava.example.lang;

public class ElapsedTimeExample {
    public static void main(String[] args) {
        // Get the start time of the process
        long start = System.nanoTime();
        System.out.println("Start: " + start);

        // Just do some a bit long process calculating the total value
        // of even number from zero to 10000
        int totalEven = 0;
        for (int i = 0; i < 10000; i++) {
            if (i % 2 == 0) {
                totalEven = totalEven + i;
            }
        }

        // Get the end time of the process
        long end = System.nanoTime();
        System.out.println("End  : " + end);

        long elapsedTime = end - start;

        // Show how long it took to finish the process
        System.out.println("The process took approximately: "
            + elapsedTime + " nano seconds");
    }
}

And example of the result are:

Start: 19286838358442
End  : 19286839756241
The process took approximately: 1397799 nano seconds