JVM Performance

Question

Hello all,
There is strange behaviour of JVM when I tested it in following way.
I created two identical classes which are simply echoing the given parameter:
     public class Echo1 {
          public int echo(int a){
               return a;
     public class Echo2 {
          public int echo(int a){
               return a;
Then I uses these classes in a Main method in order to test:
     public class TEst {
          public static void main(String[] args) throws InterruptedException {
               int count = 100000000;
               //new Echo2()
               long start = System.currentTimeMillis();          
               for(int i=0; i<count; i++){
                    (new Echo1()).echo(1111);
               long stop = System.currentTimeMillis();          
               System.out.println("-- Elapsed Time for echo1: " + (stop - start));     
               start = System.currentTimeMillis();               
               for(int i=0; i<count; i++){
                    (new Echo2()).echo(2222);
               stop = System.currentTimeMillis();          
               System.out.println("-- Elapsed Time for echo2: " + (stop - start));          
When you run these codes, you can see these lines:
-- Elapsed Time for echo1: 640
-- Elapsed Time for echo2: 10854
But when you lift the comment of "new Echo2()" coming just after the line "int count = 100000000;"
you see totally different results for echo2:
-- Elapsed Time for echo1: 634
-- Elapsed Time for echo2: 507
My question is why the performance of jvm is increasing when i add a simple line that isnt used at top?
Or why is the performance of echo2 is too bad in first run?
Thanks
Ayd&#305;n Karaman

Answer 1

Note: This thread was originally posted in the [Java Virtual Machine (JVM)|http://forums.sun.com/forum.jspa?forumID=37] forum, but moved to this forum for closer topic alignment.