This class overrides the default behaviour for transaction management. The transaction is marked for rollback, so that the HibSessionServletFilter further down the filter stack will rollback the
current transaction. For this to work, an exception mapping for the exception thrown needs to be defined in the struts.xml:
<global-results>
<result name="genericError">/error/error.jsp</result>
</global-results>
<global-exception-mappings>
<exception-mapping exception="java.lang.Exception" result="genericError"/>
</global-exception-mappings>