title: Confusion in the differences between hashmap and hashtable
body: <p>I have a confusion:</p>
  
  <p>I have read in many posts that <strong>Hash-maps</strong> are implemented as binary search trees which makes the various operations <em>time complexity of logarithmic order.</em></p>
  
  <p><strong>Hashtables</strong> on the other hand provide <em>constant time fetching.</em></p>
  
  <blockquote>
    <p>But, as I read in <a href="https://stackoverflow.com/questions/40471/differences-between-hashmap-and-hashtable">this</a> post, no difference has been provided in terms of the complexity for retrieval/searching of elements in the two data structures.</p>
  </blockquote>
  
  <p>So, here is my question-</p>
  
  <p>Since hashtables are guaranteed to provide constant searching time complexity, their implementation must differ from those of hash-maps. <em>So, why will someone ever use hash-maps if they do not provide constant time searching. Also, why in the first place, they are implemented as binary search trees?</em></p>
  
  <p>I know hash maps store the keys in sorted form and provide iteration through the map. But, the same could also be provide in the hashtable too.</p>