https://github.com/spring-projects/spring-framework: Spring Expression Language (SpEL) (Spring IO)
  • Juergen Hoeller 
Common utility classes behind the Spring Expression Language.

/**
 * Common utility classes behind the <em>Spring Expression Language</em>.
 */
@NonNullApi
@NonNullFields
package org.springframework.expression.common;

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