title: What is the initial size of Array in HashMap Architecture?
body: <p>I think <code>HashMap</code>'s internal buckets use an array to store values based on keys as in the below screenshot.  </p>
  
  <p><a href="https://i.stack.imgur.com/kF0Hh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kF0Hh.png" alt="array in HashMap"></a></p>
  
  <p>So, is the initial size of the array 16? Later if the size increases the <code>HashMap</code> internally rehashes everything? If not then what is the initial size of the array in a <code>HashMap</code>.</p>
  
  <p>Also please confirm whether it uses an array or any other data structure like <code>ArrayList</code>?</p>