code: public ActionResponse resolve(ActionRuntime runtime, RuntimeException cause) {
          final ActionResponse handledBy = handleByApplication(cause);
          final ActionResponse response;
          if (handledBy.isDefined()) { // by application
              response = handledBy;
          } else { // embedded
              if (cause instanceof LaApplicationException) {
                  final LaApplicationException appEx = (LaApplicationException) cause;
                  response = asEmbeddedApplicationException(runtime, appEx);
                  reflectEmbeddedApplicationMessagesIfExists(runtime, appEx); // saving messages to session
              } else { // e.g. framework exception
                  response = asDBFluteApplicationException(runtime, cause); // saving messages to session
              }
          }
          if (response.isDefined()) { // #hope no session gateway when API by jflute (2016/08/06)
              if (needsApplicationExceptionApiDispatch(runtime, cause, response)) { // clearing session messages (basically)
                  final ApiResponse dispatched = dispatchApiApplicationException(runtime, cause, response);
                  showApplicationExceptionHandling(runtime, cause, response);
                  return dispatched;
              }
              showApplicationExceptionHandling(runtime, cause, response);
          }
          return response;
      }
docs: Resolve the application exception thrown by (basically) action execute. <br>
  There is more flexibility than the function so you can set it here. <br>
  This is called by callback process so you should NOT call this directly in your action.
  @param runtime The runtime meta of action execute. (NotNull)
  @param cause The exception thrown by (basically) action execute, might be translated. (NotNull)
  @return The action response for application exception. (NotNull: and if defined, go to the path, UndefinedAllowed: unhandled as application exception)