title: JAVA collection object instantiation
body: <p>In most of the examples JAVA collection objects are instantiated as: </p>
  
  <pre><code>List &lt;String&gt; l1 = new LinkedList&lt;String&gt;();
  
  Set&lt;String&gt; s1 = new HashSet&lt;String&gt;();
  </code></pre>
  
  <p>Instead of:</p>
  
  <pre><code>LinkedList&lt;String&gt; l1 = new LinkedList&lt;String&gt;();
  
  HashSet&lt;String&gt; s1 = new HashSet&lt;String&gt;();
  </code></pre>
  
  <p>What is the difference in these method of instantiation ?</p>