https://github.com/FasterXML/jackson-core: Core Jackson processing abstractions (aka Streaming API), implementation for JSON (FasterXML)
  • Tatu Saloranta
  • Christopher Currie
  • Paul Brown 
Contains classes needed for type introspection, mostly used by data binding functionality. Most of this functionality is needed to properly handled generic types, and to simplify and unify processing of things Jackson needs to determine how contained types (of Collection and Map classes) are to be handled. 
 With 2.9, an additional type (WritableTypeId) was added to help handling of type identifiers needed to support polymorphic type serialization, deserialization. 
/**
 * Contains classes needed for type introspection, mostly used by data binding
 * functionality. Most of this functionality is needed to properly handled
 * generic types, and to simplify and unify processing of things Jackson needs
 * to determine how contained types (of {@link java.util.Collection} and
 * {@link java.util.Map} classes) are to be handled.
 *<p>
 * With 2.9, an additional type ({@link com.fasterxml.jackson.core.type.WritableTypeId})
 * was added to help handling of type identifiers needed to support polymorphic
 * type serialization, deserialization.
 */
package com.fasterxml.jackson.core.type;