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/FormatFeature.java

package com.fasterxml.jackson.core;

import com.fasterxml.jackson.core.util.JacksonFeature;

/**
 * Marker interface that is to be implemented by data format - specific features.
 * Interface used since Java Enums can not extend classes or other Enums, but
 * they can implement interfaces; and as such we may be able to use limited
 * amount of generic functionality.
 *<p>
 * Since 2.12 this is more of an extra marker feature, as its core API is now
 * defined in more general {@link JacksonFeature}.
 * 
 * @since 2.6
 */
public interface FormatFeature
    extends JacksonFeature // since 2.12
{
    /**
     * Accessor for checking whether this feature is enabled by default.
     */
    @Override
    public boolean enabledByDefault();
    
    /**
     * Returns bit mask for this feature instance; must be a single bit,
     * that is of form <code>(1 &lt;&lt; N)</code>
     */
    @Override
    public int getMask();

    /**
     * Convenience method for checking whether feature is enabled in given bitmask
     */
    @Override
    public boolean enabledIn(int flags);
}

⏎ com/fasterxml/jackson/core/FormatFeature.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 

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⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library