https://github.com/spring-projects/spring-framework: Spring Core (Spring IO)
  • Juergen Hoeller 
Miscellaneous utility classes, such as String manipulation utilities,
a Log4J configurer, and a state holder for paged lists of objects.

/**
 * Miscellaneous utility classes, such as String manipulation utilities,
 * a Log4J configurer, and a state holder for paged lists of objects.
 */
@NonNullApi
@NonNullFields
package org.springframework.util;

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