title: How ArrayList provides random access behaviour?
body: <p>ArrayList is simply implemented as an Object[]. I know it implements the <code>RandomAccess</code> interface, but it is only a marker interface...</p>
  
  <p>So, my question is: Why/How ArrayList provides the random access feature?</p>
  
  <p>EDIT 1: perhaps I should make this clearer...what I want to understand is why it is constant time to access the element while it is an Object[]?</p>