Question

How to measure execution time of a method in Java

Answer 1

public class MeasureExecutionTimeOfMethod_Java {
    public static long AMethod() {
        long sum = 0;
         
        for (int i = 0; i < 100000; i++) {
            sum += i;
        }
         
        return sum;
    }
     
    public static void main(String[] args) {
        long startTime = System.nanoTime();
 
        long result = AMethod();
 
        long endTime = System.nanoTime();
        long elapsedTime = endTime - startTime;
 
        System.out.println("Execution time in nanoseconds: " + elapsedTime);
        System.out.println("Execution time in milliseconds: " + elapsedTime / 1000000.0);
    }
}

    
    
/*
run:
        
Execution time in nanoseconds: 1170810
Execution time in milliseconds: 1.17081
 
*/

 

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Answer 2

import java.util.concurrent.TimeUnit;

public class MyClass {
    public static void AMethod() throws InterruptedException {
        TimeUnit.SECONDS.sleep(2);
    }
    
    public static void main(String[] args) {
        try {
              
            long startTime = System.nanoTime();

            AMethod();

            long endTime = System.nanoTime();
            long elapsedTime = endTime - startTime;

            System.out.println("Execution time in nanoseconds: " + elapsedTime);
            System.out.println("Execution time in milliseconds: " + elapsedTime / 1_000_000);
            System.out.println("Execution time in seconds: " + TimeUnit.SECONDS.convert(elapsedTime, TimeUnit.NANOSECONDS));
 
        } catch (InterruptedException ie) {
            System.out.println(ie);
        }
    }
}
   
   
   
   
   
/*
run:
       
Execution time in nanoseconds: 2000636786
Execution time in milliseconds: 2000
Execution time in seconds: 2

*/

 

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