title: How is empty node tag in xml and non-existence of node interpreted?
body: <p>I have two XML request:</p>
  
  <pre><code>&lt;GetPersonRequest&gt;
      &lt;Person/&gt;
      &lt;IncludeAddress&gt;true&lt;/IncludeAddress&gt;
  &lt;/GetPersonRequest&gt;
  </code></pre>
  
  <p>and</p>
  
  <pre><code>&lt;GetPersonRequest&gt;
      &lt;IncludeAddress&gt;true&lt;/IncludeAddress&gt;
  &lt;/GetPersonRequest&gt;
  </code></pre>
  
  <p>Is there a difference between empty nodes and non-existence of nodes ? Does the XML parser makes any difference ?. Does call to text of both node returns empty string ? </p>
  
  <p>I would like to add that second XML is similar in that element is optional. So the user might just omit. Does xml.getElement("Person") still return null ?</p>