Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Core Source Code files are provided in the source packge (jackson-core-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Core Source Code below:

⏎ com/fasterxml/jackson/core/util/Instantiatable.java

package com.fasterxml.jackson.core.util;

/**
 * Add-on interface used to indicate things that may be "blueprint" objects
 * which can not be used as is, but are used for creating usable per-process
 * (serialization, deserialization) instances, using
 * {@link #createInstance} method.
 *<p>
 * Note that some implementations may choose to implement {@link #createInstance}
 * by simply returning 'this': this is acceptable if instances are stateless.
 * 
 * @see DefaultPrettyPrinter
 * 
 * @since 2.1
 */
public interface Instantiatable<T>
{
    /**
     * Method called to ensure that we have a non-blueprint object to use;
     * it is either this object (if stateless), or a newly created object
     * with separate state.
     *
     * @return Actual instance to use
     */
    T createInstance();
}

⏎ com/fasterxml/jackson/core/util/Instantiatable.java

Or download all of them as a single archive file:

File name: jackson-core-2.14.0-sources.jar
File size: 497693 bytes
Release date: 2022-11-05
Download 

⇒ Download and Install Jackson Binary Package

⇐ What Is Jackson

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library