title: Why Collections.sort uses merge sort instead of quicksort?
body: <p>We know that quick sort is the fastest sorting algorithm.</p>
  
  <p>The JDK6 <code>collections.sort</code> uses the merge sort algorithm instead of quick sort. But Arrays.sort uses quick sort algorithm.</p>
  
  <p>What is the reason Collections.sort uses merge sort instead of quick sort? </p>