<p>This class makes use of internal api classes. As these
classes are not documented, nor externally released as part of the api, they are subject
to change or removal. You should not be using these classes.</p>
Packages that shouldn't be used are:
<ul>
  <li>com.sun.xxx</li>
  <li>org.apache.xerces.xxx</li>
  <li>org.apache.xalan.xxx</li>
</ul>