public class HSQLShutdown extends BaseServlet
This servlet does not handle requests, so it is not necessary to defined servlet-mapping sections for it. The following lines in web.xml are sufficient to enable clean HSQL shutdowns:
 <servlet>
     <servlet-name>HSQLShutdown</servlet-name>
     <servlet-class>com.isomorphic.sql.HSQLShutdown</servlet-class>
     <load-on-startup>3</load-on-startup>
 </servlet>
 handleError, handleError