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

Jackson Annotations Source Code files are provided in the source packge (jackson-annotations-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Annotations Source Code below:

⏎ com/fasterxml/jackson/databind/ext/DOMDeserializer.java

package com.fasterxml.jackson.databind.ext;

import java.io.StringReader;

import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;

import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.FromStringDeserializer;

/**
 * Base for serializers that allows parsing DOM Documents from JSON Strings.
 * Nominal type can be either {@link org.w3c.dom.Node} or
 * {@link org.w3c.dom.Document}.
 */
public abstract class DOMDeserializer<T> extends FromStringDeserializer<T>
{
    private static final long serialVersionUID = 1L;

    private final static DocumentBuilderFactory DEFAULT_PARSER_FACTORY;
    static {
        DocumentBuilderFactory parserFactory = DocumentBuilderFactory.newInstance();
        // yup, only cave men do XML without recognizing namespaces...
        parserFactory.setNamespaceAware(true);
        // [databind#1279]: make sure external entities NOT expanded by default
        parserFactory.setExpandEntityReferences(false);
        // ... and in general, aim for "safety"
        try {
            parserFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
        } catch(ParserConfigurationException pce) {
            // not much point to do anything; could log but...
        } catch (Error e) {
            // 14-Jul-2016, tatu: Not sure how or why, but during code coverage runs
            //   (via Cobertura) we get `java.lang.AbstractMethodError` so... ignore that too
        }

        // [databind#2589] add two more settings just in case
        try {
            parserFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
        } catch (Throwable t) { } // as per previous one, nothing much to do
        try {
            parserFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
        } catch (Throwable t) { } // as per previous one, nothing much to do
        DEFAULT_PARSER_FACTORY = parserFactory;
    }

    protected DOMDeserializer(Class<T> cls) { super(cls); }

    @Override
    public abstract T _deserialize(String value, DeserializationContext ctxt);

    protected final Document parse(String value) throws IllegalArgumentException {
        try {
            return documentBuilder().parse(new InputSource(new StringReader(value)));
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to parse JSON String as XML: "+e.getMessage(), e);
        }
    }

    /**
     * Overridable factory method used to create {@link DocumentBuilder} for parsing
     * XML as DOM.
     *
     * @since 2.7.6
     */
    protected DocumentBuilder documentBuilder() throws ParserConfigurationException {
        return DEFAULT_PARSER_FACTORY.newDocumentBuilder();
    }

    /*
    /**********************************************************
    /* Concrete deserializers
    /**********************************************************
     */
    
    public static class NodeDeserializer extends DOMDeserializer<Node> {
        private static final long serialVersionUID = 1L;
        public NodeDeserializer() { super(Node.class); }
        @Override
        public Node _deserialize(String value, DeserializationContext ctxt) throws IllegalArgumentException {
            return parse(value);
        }
    }    

    public static class DocumentDeserializer extends DOMDeserializer<Document> {
        private static final long serialVersionUID = 1L;
        public DocumentDeserializer() { super(Document.class); }
        @Override
        public Document _deserialize(String value, DeserializationContext ctxt) throws IllegalArgumentException {
            return parse(value);
        }
    }    
}

⏎ com/fasterxml/jackson/databind/ext/DOMDeserializer.java

 

⇒ Jackson Dataformat Extensions

⇐ Jackson Data Binding Source Code

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library