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/ser/ContainerSerializer.java

package com.fasterxml.jackson.databind.ser;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

/**
 * Intermediate base class for serializers used for serializing
 * types that contain element(s) of other types, such as arrays,
 * {@link java.util.Collection}s (<code>Lists</code>, <code>Sets</code>
 * etc) and {@link java.util.Map}s and iterable things
 * ({@link java.util.Iterator}s).
 */
@SuppressWarnings("serial")
public abstract class ContainerSerializer<T>
    extends StdSerializer<T>
{
    /*
    /**********************************************************
    /* Construction, initialization
    /**********************************************************
     */

    protected ContainerSerializer(Class<T> t) {
        super(t);
    }

    /**
     * @since 2.5
     */
    protected ContainerSerializer(JavaType fullType) {
        super(fullType);
    }
    
    /**
     * Alternate constructor that is (alas!) needed to work
     * around kinks of generic type handling
     * 
     * @param t
     */
    protected ContainerSerializer(Class<?> t, boolean dummy) {
        super(t, dummy);
    }

    protected ContainerSerializer(ContainerSerializer<?> src) {
        super(src._handledType, false);
    }
    
    /**
     * Factory(-like) method that can be used to construct a new container
     * serializer that uses specified {@link TypeSerializer} for decorating
     * contained values with additional type information.
     * 
     * @param vts Type serializer to use for contained values; can be null,
     *    in which case 'this' serializer is returned as is
     * @return Serializer instance that uses given type serializer for values if
     *    that is possible (or if not, just 'this' serializer)
     */
    public ContainerSerializer<?> withValueTypeSerializer(TypeSerializer vts) {
        if (vts == null) return this;
        return _withValueTypeSerializer(vts);
    }

    /*
    /**********************************************************
    /* Extended API
    /**********************************************************
     */

    /**
     * Accessor for finding declared (static) element type for
     * type this serializer is used for.
     */
    public abstract JavaType getContentType();

    /**
     * Accessor for serializer used for serializing contents
     * (List and array elements, Map values etc) of the
     * container for which this serializer is used, if it is
     * known statically.
     * Note that for dynamic types this may return null; if so,
     * caller has to instead use {@link #getContentType()} and
     * {@link com.fasterxml.jackson.databind.SerializerProvider#findContentValueSerializer}.
     */
    public abstract JsonSerializer<?> getContentSerializer();

    /*
    /**********************************************************
    /* Abstract methods for sub-classes to implement
    /**********************************************************
     */

// since 2.5: should be declared abstract in future (2.9?)
//    @Override
//    public abstract boolean isEmpty(SerializerProvider prov, T value);

    /**
     * Method called to determine if the given value (of type handled by
     * this serializer) contains exactly one element.
     *<p>
     * Note: although it might seem sensible to instead define something
     * like "getElementCount()" method, this would not work well for
     * containers that do not keep track of size (like linked lists may
     * not).
     *<p>
     * Note, too, that as of now (2.9) this method is only called by serializer
     * itself; and specifically is not used for non-array/collection types
     * like <code>Map</code> or <code>Map.Entry</code> instances.
     */
    public abstract boolean hasSingleElement(T value);

    /**
     * Method that needs to be implemented to allow construction of a new
     * serializer object with given {@link TypeSerializer}, used when
     * addition type information is to be embedded.
     */
    protected abstract ContainerSerializer<?> _withValueTypeSerializer(TypeSerializer vts);

    /*
    /**********************************************************
    /* Helper methods for sub-types
    /**********************************************************
     */

    /**
     * Helper method used to encapsulate logic for determining whether there is
     * a property annotation that overrides element type; if so, we can
     * and need to statically find the serializer.
     * 
     * @since 2.1
     *
     * @deprecated Since 2.7: should not be needed; should be enough to see if
     *     type has 'isStatic' modifier
     */
    @Deprecated
    protected boolean hasContentTypeAnnotation(SerializerProvider provider,
            BeanProperty property)
    {
        /*
        if (property != null) {
            AnnotationIntrospector intr = provider.getAnnotationIntrospector();
            AnnotatedMember m = property.getMember();
            if ((m != null) && (intr != null)) {
                if (intr.findSerializationContentType(m, property.getType()) != null) {
                    return true;
                }
            }
        }
        */
        return false;
    }
}

⏎ com/fasterxml/jackson/databind/ser/ContainerSerializer.java

 

⇒ Jackson Dataformat Extensions

⇐ Jackson Data Binding Source Code

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library