Optimization on for loops with ArrayLists
<p>From <a href="http://developer.android.com/guide/practices/design/performance.html#foreach" rel="nofollow">this</a> article, </p>

<blockquote>
  <p>hand-written counted loop is about 3x faster</p>
</blockquote>

<p>than an enhanced for loop for iterating over arraylists. </p>

<p>Firstly, what do they mean by "hand-written counted loop"? They didn't explicitly elaborate what this means. Secondly, why is it that this holds true only for arraylists and not the other collections?</p>
