l</dd>
<dt><span class="strong">Returns:</span></dt><dd>null if all good, otherwise the first test that fails.</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="http://download.oracle.com/javase/7/docs/api/javax/xml/xpath/XPathExpressionException.html?is-external=true" title="class or interface in javax.xml.xpath">XPathExpressionException</a></code></dd>
<dd><code><a href="http://download.oracle.com/javase/7/docs/api/org/xml/sax/SAXException.html?is-external=true" title="class or interfac