title: Passing empty string to .tag with a java.lang.Integer attribute results in 0 (not null)
body: <p>I have a .tag file with an attribute of type java.lang.Integer like so:</p>
  
  <pre><code>&lt;%@ attribute name="userId" required="true" type="java.lang.Integer"%&gt;
  </code></pre>
  
  <p>When passing in an empty string to this tag, the attribute ends up with a value of <strong>0</strong> instead of <strong>null</strong> (as I would have hoped using <strong>java.lang.Integer</strong> and all).</p>
  
  <p>Am I missing something?  Is there any way to force the attribute value to be <strong>null</strong> in this case?</p>