Spring Validation Setup ~ CompositeValidator

CompositeValidator.java

@Component
public class CompositeValidator implements SmartValidator {
    @Autowired
    private List<Validator> validators = Collections.emptyList();

    @PostConstruct
    public void init() {
        Collections.sort(validators, AnnotationAwareOrderComparator.INSTANCE);
    }

    @Override
    public boolean supports(Class<?> clazz) {
         for (Validator validator : validators) {
            if (validator.supports(clazz)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void validate(Object target, Errors errors) {
        validate(target, errors, javax.validation.groups.Default.class);
    }

    @Override
    public void validate(Object target, Errors errors, Object... validationHints) {
        Class<?> clazz = target.getClass();

        for (Validator validator : validators) {
            if (validator.supports(clazz)) {
                if (validator instanceof SmartValidator) {
                    ((SmartValidator) validator).validate(target, errors, validationHints);
                } else {
                    validator.validate(target, errors);
                }
            }
        }
    }
}

SomeController.java

@Controller
@RequestMapping("/my/resources")
public class SomeController {

    @RequestMapping(method = RequestMethod.POST)
    public Object save(
            @Validated(javax.validation.groups.Default.class) // this interface descriptor (class) is used by default
            @RequestBody MyResource myResource
    ) { return null; }
}

WebConfig.java

@Configuration
public class WebConfig {
    /** used for Annotation based validation, it can be created by spring automaticaly and you don't do it manualy */
    // @Bean
    // public Validator jsr303Validator() {
    //   LocalValidatorFactoryBean validator = new LocalValidatorFactoryBean();
    //   // validator.setValidationMessageSource(...);
    //   return validator;
    // }
    
    @Bean
    public WebMvcConfigurerAdapter webMvcConfigurerAdapter() {
        return new WebMvcConfigurerAdapter() {
            @Autowired
            private CompositeValidator validator;

            @Override
            public Validator getValidator() {
                return validator;
            }
        }
    }
}

webmvc-config.xml

<!-- used for Annotation based validation, it can be created by spring automaticaly and you don't do it manualy -->
<!--<bean id="jsr303Validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean">-->
<!--  <property name="validationMessageSource" ref="messageSource"/>-->
<!--</bean>-->

<mvc:annotation-driven validator="compositeValidator">
  //...
</mvc:annotation-driven>