Annotation Type Valid

@Retention(CLASS)
@Target({FIELD,PARAMETER})
public @interface Valid

Validates the annotated value's own constraints.

On a @RequestBody or @ModelAttribute parameter it asks the build to check the bound object before the controller method runs; on a field of such an object it descends into the field's value -- each element of a collection or array -- and reports its violations under the field's path (address.zip, items[2].name). The checks are generated code, so the classes need no reflection at run time.