 type conversion.</p>

 <p>If <code>returnType</code> is not one of the types defined 
 in <A HREF="../../../../javax/xml/xpath/XPathConstants.html"><CODE>XPathConstants</CODE></A>,
 then an <code>IllegalArgumentException</code> is thrown.</p>

 <p>If a <code>null</code> value is provided for
 <code>item</code>, an empty document will be used for the
 context.
 If <code>returnType</code> is <code>null</code>, then a 
 <code>NullPointerException</code> is thrown.</p><DD><DL>
<DT><B>Specified by: </B><DD><A H