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

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

You can also browse Jackson Databind Source Code below:

⏎ com/fasterxml/jackson/databind/deser/impl/SetterlessProperty.java

package com.fasterxml.jackson.databind.deser.impl;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.NullValueProvider;
import com.fasterxml.jackson.databind.deser.SettableBeanProperty;
import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
import com.fasterxml.jackson.databind.introspect.AnnotatedMethod;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.util.Annotations;

/**
 * This concrete sub-class implements Collection or Map property that is
 * indirectly by getting the property value and directly modifying it.
 */
public final class SetterlessProperty
    extends SettableBeanProperty
{
    private static final long serialVersionUID = 1L;

    protected final AnnotatedMethod _annotated;

    /**
     * Get method for accessing property value used to access property
     * (of Collection or Map type) to modify.
     */
    protected final Method _getter;

    public SetterlessProperty(BeanPropertyDefinition propDef, JavaType type,
            TypeDeserializer typeDeser, Annotations contextAnnotations, AnnotatedMethod method)
    {
        super(propDef, type, typeDeser, contextAnnotations);
        _annotated = method;
        _getter = method.getAnnotated();
    }

    protected SetterlessProperty(SetterlessProperty src, JsonDeserializer<?> deser,
            NullValueProvider nva) {
        super(src, deser, nva);
        _annotated = src._annotated;
        _getter = src._getter;
    }

    protected SetterlessProperty(SetterlessProperty src, PropertyName newName) {
        super(src, newName);
        _annotated = src._annotated;
        _getter = src._getter;
    }

    @Override
    public SettableBeanProperty withName(PropertyName newName) {
        return new SetterlessProperty(this, newName);
    }

    @Override
    public SettableBeanProperty withValueDeserializer(JsonDeserializer<?> deser) {
        if (_valueDeserializer == deser) {
            return this;
        }
        // 07-May-2019, tatu: As per [databind#2303], must keep VD/NVP in-sync if they were
        NullValueProvider nvp = (_valueDeserializer == _nullProvider) ? deser : _nullProvider;
        return new SetterlessProperty(this, deser, nvp);
    }

    @Override
    public SettableBeanProperty withNullProvider(NullValueProvider nva) {
        return new SetterlessProperty(this, _valueDeserializer, nva);
    }

    @Override
    public void fixAccess(DeserializationConfig config) {
        _annotated.fixAccess(
                config.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
    }

    /*
    /**********************************************************
    /* BeanProperty impl
    /**********************************************************
     */
    
    @Override
    public <A extends Annotation> A getAnnotation(Class<A> acls) {
        return _annotated.getAnnotation(acls);
    }

    @Override public AnnotatedMember getMember() {  return _annotated; }

    /*
    /**********************************************************
    /* Overridden methods
    /**********************************************************
     */
    
    @Override
    public final void deserializeAndSet(JsonParser p, DeserializationContext ctxt,
            Object instance) throws IOException
    {
        if (p.hasToken(JsonToken.VALUE_NULL)) {
            // Hmmh. Is this a problem? We won't be setting anything, so it's
            // equivalent of empty Collection/Map in this case
            return;
        }
        // For [databind#501] fix we need to implement this but:
        if (_valueTypeDeserializer != null) {
            ctxt.reportBadDefinition(getType(), String.format(
                    "Problem deserializing 'setterless' property (\"%s\"): no way to handle typed deser with setterless yet",
                    getName()));
//            return _valueDeserializer.deserializeWithType(p, ctxt, _valueTypeDeserializer);
        }
        // Ok: then, need to fetch Collection/Map to modify:
        Object toModify;
        try {
            toModify = _getter.invoke(instance, (Object[]) null);
        } catch (Exception e) {
            _throwAsIOE(p, e);
            return; // never gets here
        }
        // Note: null won't work, since we can't then inject anything in. At least
        // that's not good in common case. However, theoretically the case where
        // we get JSON null might be compatible. If so, implementation could be changed.
        if (toModify == null) {
            ctxt.reportBadDefinition(getType(), String.format(
                    "Problem deserializing 'setterless' property '%s': get method returned null",
                    getName()));
        }
        _valueDeserializer.deserialize(p, ctxt, toModify);
    }

    @Override
    public Object deserializeSetAndReturn(JsonParser p,
    		DeserializationContext ctxt, Object instance) throws IOException
    {
        deserializeAndSet(p, ctxt, instance);
        return instance;
    }

    @Override
    public final void set(Object instance, Object value) throws IOException {
        throw new UnsupportedOperationException("Should never call `set()` on setterless property ('"+getName()+"')");
    }

    @Override
    public Object setAndReturn(Object instance, Object value) throws IOException
    {
        set(instance, value);
        return instance;
    }
}

⏎ com/fasterxml/jackson/databind/deser/impl/SetterlessProperty.java

Or download all of them as a single archive file:

File name: jackson-databind-2.14.0-sources.jar
File size: 1187952 bytes
Release date: 2022-11-05
Download 

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⇐ Download and Install Jackson Binary Package

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library