title: questions on using hashset to define a new set
body: <p>With respect to the following two different definitions of sets, what are the differences:</p>
  
  <pre><code>Set&lt;Integer&gt; intset = new Hashset&lt;Integer&gt;();
  
  Set&lt;Integer&gt; intset = new Set&lt;Integer&gt;();
  </code></pre>
  
  <p>Thanks.</p>