d.
 <p>
 Calling this method with a null parameter will cause the Validator
 to revert back to the default default event handler.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>handler</code> - the validation event handler</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../jakarta/xml/bind/JAXBException.html" title="class in jakarta.xml.bind">JAXBException</a></code> - if an error was encountered while setting the
         event handler</dd>
</dl>
<