https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
  • Juergen Hoeller 
Support classes for annotation-based constraint evaluation,
e.g. using a JSR-303 Bean Validation provider.

Provides an extended variant of JSR-303's @Valid, supporting the specification of validation groups. 
/**
 * Support classes for annotation-based constraint evaluation,
 * e.g. using a JSR-303 Bean Validation provider.
 *
 * <p>Provides an extended variant of JSR-303's {@code @Valid},
 * supporting the specification of validation groups.
 */
@NonNullApi
@NonNullFields
package org.springframework.validation.annotation;

import org.springframework.lang.NonNullApi;
import org.springframework.lang.NonNullFields;