Form validators such as the new RegexValidator do not override the validateWithResult method but instead the old validate method. And as mentioned in MGNLFORM-79 this causes the old behaviour where only the default error messages defined in the form module resource bundle itself are used. And so people that use say the RegexValidator class are not able to define their own error messages (in their own module's resource bundles). As suggested in MGNLFORM-79, we should deprecate the Validator#validate method in favor of the validateWithResult method.