</code> or <code>returnType</code> is <code>null</code>,
 then a <code>NullPointerException</code> is thrown.</p><DD><DL>
<DT><B>Specified by: </B><DD><A HREF="../../../../javax/xml/xpath/XPathExpression.html#evaluate(org.xml.sax.InputSource, javax.xml.namespace.QName)">evaluate</A> in interface <A HREF="../../../../javax/xml/xpath/XPathExpression.html">XPathExpression</A><DT><B>Parameters:</B><DD><CODE>source</CODE> - The <code>InputSource</code> of the document to evaluate
 over.<DD><CODE>returnType</CODE