 if the Unmarshaller should validate during 
        unmarshal, false otherwise</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="JAXBException.html" title="class in jakarta.xml.bind">JAXBException</a></code> - if an error occurred while enabling or disabling
         validation at unmarshal time</dd>
<dd><code>java.lang.UnsupportedOperationException</code> - could be thrown if this method is
         invoked on an Unmarshaller created from a JAXBContext referencing
         Jakarta 