How to measure elapsed time in nanoseconds with Java?

In general, the elapsed time is the time from the starting point to ending point of an event. Following are various ways to find elapsed time in Java −

The nanoTime() method returns the current time in nano seconds. To find the elapsed time for the execution of a method in nano seconds −

• Retrieve the current time using the nanoTime() method.
• Execute the desired method.
• Again, retrieve the current time using the nanoTime() method.
• Finally, Find the difference between the end value and the start value.

Example

public class Example {
   public void test(){
      int num = 0;
      for(int i=0; i<=50; i++){  
         num =num+i;
         System.out.print(num+", ");
      }      
   }
   public static void main(String args[]){  
      //Start time
      long begin = System.nanoTime();
      //Starting the watch
      new Example().test();
      //End time
      long end = System.nanoTime();          
      long time = end-begin;
      System.out.println();
      System.out.println("Elapsed Time: "+time);
   }
}

Output

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 666, 703, 741, 780, 820, 861, 903, 946, 990, 1035, 1081, 1128, 1176, 1225, 1275,
Elapsed Time: 1530200