why is the enhanced for loop more efficient than the normal for loop

Question

I read that the enhanced for loop is more efficient than the normal for loop here:

http://developer.android.com/guide/practices/performance.html#fo

Answer 1

I am myself surprised in a little experiment i did today with above mentioned points. So what i did was that i inserted a certain number of elements to a linked list and iterated through it using the above mentioned three methods 1)using advanced for loop 2) using Iterator 3) using simple loop and get()
I guess programmers such as you guys can better understand what i did by seeing the code.

long advanced_timeElapsed,iterating_timeElapsed,simple_timeElapsed;
    long first=System.nanoTime();
    for(Integer i: myList){
        Integer b=i;
    }
    long end= System.nanoTime();
    advanced_timeElapsed=end-first;
    System.out.println("Time for Advanced for loop:"+advanced_timeElapsed);
    first=System.nanoTime();
    Iterator it = myList.iterator();
    while(it.hasNext())
    {
        Integer b=it.next();
    }
    end= System.nanoTime();
    iterating_timeElapsed=end-first;
    System.out.println("Time for Iterating Loop:"+iterating_timeElapsed);
    first=System.nanoTime();
    int counter=0;
    int size= myList.size();
    while(counter

The results where not what i expected . Following is the graph of time elapsed in 3 cases.

Y axis-time elapsed X axis-test case
test case1:10 inputs
test case2:30 inputs
test case3:50 inputs
test case4:100 inputs
test case5:150 inputs
test case6:300 inputs
test case7:500 inputs
test case8:1000 inputs
test case9:2000 inputs
test case10:5000 inputs
test case11:10000 inputs
test case12:100000 inputs

Here you can see that simple loop performs way better than others.if you find any errors in the code above , do reply and i will check again. will update on this further after i dig through bytecode and see what is happening under the hood. My apologies for such a long response but i like to be descriptive. Philip