Java test: Iterator foreach for three iterations in what way is it faster?

Code:

 Public classMain { Public Static voidMain (string[] p_args) {ArrayList<String> _l_string =NewArraylist<>();  for(into_a = 0; O_a < 100000; o_a++) {_l_string.add (string.valueof (o_a)); } c_public_counttime _counttime=NewC_public_counttime ();        _counttime.f_begin ();  for(inti = 0; I < _l_string.size (); i++) {System.out.print (_l_string.get (i)); } String _time_for=_counttime.f_done ();        _counttime.f_begin ();  for(String o_a: _l_string) {System.out.print (o_a); } String _time_foreach=_counttime.f_done ();        _counttime.f_begin ();  for(Iterator<string> O_iterator =_l_string.iterator (); O_iterator.hasnext ();)        {System.out.print (O_iterator.next ()); } String _time_iterator=_counttime.f_done (); System.out.println ("\niterator:" + _time_iterator + "\nfor:" + _time_for + "\nforeach:" +_time_foreach); }}

The result: it may be because of the internal execution of Java, the different order caused by the length of the various, here collected a little data samples.

(Speed, sequencing, duration)

#2 for:354 milliseconds

#1 foreach:263 milliseconds

#3 iterator:425 milliseconds

Summary: A for after foreach adds speed.

=

#1 for:285 milliseconds

#2 iterator:301 milliseconds

#3 foreach:363 milliseconds

Summary: For the first appearance also got the fastest speed.

===

#3 foreach:517 milliseconds

#1 for:285 milliseconds

#2 iterator:478 milliseconds

Summary: foreach first appearance is not fast, the for speed is the same as the first appearance speed.

=

#3 foreach:416 milliseconds

#1 iterator:317 milliseconds

#2 for:321 milliseconds

Summary: Even when the iterator get the fastest speed, for there is almost no difference in speed.

===

#2 iterator:396 milliseconds

#3 foreach:415 milliseconds

#1 for:253 milliseconds

Summary: For the last appearance of the time to get the fastest speed.

===

#3 iterator:417 milliseconds
#1 for:332 milliseconds
#2 foreach:334 milliseconds

Summary: For the best speed.

Summary: Iterator and foreach do not increase the speed of the iteration. So you should use them for the necessary reasons, or the default for is faster.

Java test: Iterator foreach for three iterations in what way is it faster?