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/async/NonBlockingInputFeeder.java

package com.fasterxml.jackson.core.async;

/**
 * Interface used by non-blocking {@link com.fasterxml.jackson.core.JsonParser}
 * implementations to feed input to parse.
 * Feeder is used by entity that feeds content to parse; at any given point
 * only one chunk of content can be processed so caller has to take care to
 * only feed more content when existing content has been parsed (which occurs
 * when parser's <code>nextToken</code> is called). Once application using
 * non-blocking parser has no more data to feed it should call
 * {@link #endOfInput} to indicate end of logical input (stream) to parse.
 *
 * @since 2.9
 */
public interface NonBlockingInputFeeder
{
    /**
     * Method called to check whether it is ok to feed more data: parser returns true
     * if it has no more content to parse (and it is ok to feed more); otherwise false
     * (and no data should yet be fed).
     *
     * @return {@code True} if more input is needed (and can be fed); {@code false} if
     *    there is still some input to decode
     */
    public boolean needMoreInput();

    /**
     * Method that should be called after last chunk of data to parse has been fed
     * (with {@code feedInput} in sub-class); can be called regardless of what
     * {@link #needMoreInput}
     * returns. After calling this method, no more data can be fed; and parser assumes
     * no more data will be available.
     */
    public void endOfInput();
}

⏎ com/fasterxml/jackson/core/async/NonBlockingInputFeeder.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
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⇑⇑ Jackson - Java JSON library