title: OOP: Difference between ArrayList al = new ArrayList() and List al = new ArrayList()?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/4062982/list-versus-arraylist">List versus ArrayList</a>  </p>
  </blockquote>
  
  
  
  <p>Difference between </p>
  
  <pre><code>ArrayList al = new ArrayList() 
  </code></pre>
  
  <p>and </p>
  
  <pre><code>List al = new ArrayList() ?
  </code></pre>