How do I calculate process elapsed time in Java?

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.

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");
    }
}

Below is the output...

Start: 14113495997955
End  : 14113497072393
The process took approximately: 1074438 nano seconds