https://github.com/spring-projects/spring-framework: Spring Web (Spring IO)
  • Juergen Hoeller 
Contains a basic abstraction over client/server-side HTTP. This package contains the HttpInputMessage and HttpOutputMessage interfaces. 
/**
 * Contains a basic abstraction over client/server-side HTTP. This package contains
 * the {@code HttpInputMessage} and {@code HttpOutputMessage} interfaces.
 */
@NonNullApi
@NonNullFields
package org.springframework.http;

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