<transition on-exception="web.appl.exceptions.SystemException" to="authenticate" /> 

 <exception-handler bean="webflowExceptionController"/> 

@Component
public class WebflowExceptionController extends TransitionExecutingFlowExecutionExceptionHandler {
	
	@PostConstruct
	private void init(){
		add(SystemException.class, "authenticate");
	}
}

public Event authenticate(AuthenticationForm authenticationForm, MvcExternalContext externalContext, MessageContext messageContext) {
 try {
       authenticate(authenticationForm, ((HttpServletRequest)
       externalContext.getNativeRequest()).getSession());
 } catch (AuthenticationException authenticationException) {
      messageContext.addMessage(new
     MessageBuilder().error().code(LOGIN_FAILED_KEY).build());
     return new EventFactorySupport().error(this);
 }
}

	@Bean
    public SimpleMappingExceptionResolver simpleMappingExceptionResolver(){
		SimpleMappingExceptionResolver resolver = new SimpleMappingExceptionResolver();
		Properties mappings = new Properties();
		
		mappings.put(Exception.class.getName(), "error");
		
		resolver.setExceptionMappings(mappings);
		resolver.setDefaultErrorView("error");
		return resolver;
	}

<error-page>
    <error-code>404</error-code>
    <location>/pageNotFound</location>
</error-page>

<%
Exception ex = (Exception) request.getAttribute("exception");
%>

<H2>Data access failure: <%= ex.getMessage() %></H2>
<P>


<%
ex.printStackTrace(new java.io.PrintWriter(out));
%>