sents the actual unmapped exception thrown
 during the request processing, before it has been wrapped into an I/O container-specific
 exception that was used to propagate the throwable to the hosting I/O container.
 </p></div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>throwable</code> - is <code>null</code>, if the request processing has completed with a response
                  that has been sent to the client. In case the request processing resulted
                  in an unma