public DefaultValidationRuleElementHandlerRegistry() {
String namepsaceUri = DefaultXmlBeanValidationConfigurationLoader.DEFAULT_NAMESPACE_URL;
// registering class handlers
registerClassHandler(new ExpressionClassValidationElementHandler(namepsaceUri));
// registering property handlers
registerPropertyHandler(new NotNullRuleElementHandler(namepsaceUri));
registerPropertyHandler(new LengthRuleElementHandler(namepsaceUri));
registerPropertyHandler(new EmailRuleElementHandler(namepsaceUri));