https://github.com/spring-projects/spring-framework: Spring Web (Spring IO)
  • Juergen Hoeller 
Common, generic interfaces that define minimal boundary points
between Spring's web infrastructure and other framework modules.

/**
 * Common, generic interfaces that define minimal boundary points
 * between Spring's web infrastructure and other framework modules.
 */
@NonNullApi
@NonNullFields
package org.springframework.web;

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