Jackson Core
org.codehaus.jackson Main public API classes of the core streaming JSON processor: most importantly JsonFactory used for constructing JSON parser (JsonParser) and generator (JsonParser) instances.
org.codehaus.jackson.annotate Public core annotations, most of which are used to configure how Data Mapping/Binding works.
org.codehaus.jackson.format Package that contains interfaces needed for dynamic, pluggable format (auto)detection; as well as basic utility classes for simple format detection functionality.
org.codehaus.jackson.impl Parser and generator implementation classes that Jackson defines and uses.
org.codehaus.jackson.io This package contains I/O helper classes Jackson itself uses, but that are not exposed for external reuse.
org.codehaus.jackson.sym Internal implementation classes for efficient handling of of symbols in JSON (field names in Objects)
org.codehaus.jackson.type Contains classes needed for type introspection, mostly used by data binding functionality.
org.codehaus.jackson.util Utility classes used by Jackson Core functionality.

 

Jackson Mapper
org.codehaus.jackson.map Contains basic mapper (conversion) functionality that allows for converting between regular streaming json content and Java objects (beans or Tree Model: support for both is via ObjectMapper class, as well as convenience methods included in JsonParser
org.codehaus.jackson.map.annotate Annotations that directly depend on Mapper classes (not just Jackson core) and are used for configuring Data Mapping functionality.
org.codehaus.jackson.map.deser Contains implementation classes of deserialization part of data binding.
org.codehaus.jackson.map.deser.impl  
org.codehaus.jackson.map.exc  
org.codehaus.jackson.map.ext Contains extended support for "external" packages: things that may or may not be present in runtime environment, but that are commonly enough used so that explicit support can be added.
org.codehaus.jackson.map.introspect Functionality needed for Bean introspection, required for detecting accessors and mutators for Beans, as well as locating and handling method annotations.
org.codehaus.jackson.map.jsontype Package that contains interfaces that define how to implement functionality for dynamically resolving type during deserialization.
org.codehaus.jackson.map.jsontype.impl Package that contains standard implementations for TypeResolverBuilder and TypeIdResolver.
org.codehaus.jackson.map.module Package that contains classes and interfaces to help implement custom extension Modules (which are registered using ObjectMapper.registerModule(org.codehaus.jackson.map.Module).
org.codehaus.jackson.map.ser Contains implementation classes of serialization part of data binding.
org.codehaus.jackson.map.ser.impl Contains implementation classes of serialization part of data binding.
org.codehaus.jackson.map.type Package that contains concrete implementations of JavaType, as well as the factory (TypeFactory) for constructing instances from various input data types (like Class, Type) and programmatically (for structured types, arrays, Lists and Maps).
org.codehaus.jackson.map.util Utility classes for Mapper package.
org.codehaus.jackson.node Contains concrete JsonNode implementations Jackson uses for the Tree model.
org.codehaus.jackson.schema Classes needed for JSON schema support (currently just ability to generate schemas using serialization part of data mapping)

 

Jackson JAX-RS provider
org.codehaus.jackson.jaxrs Jackson-based JAX-RS provider that can automatically serialize and deserialize resources for JSON content type (MediaType).

 

Jackson XML Compatibility
org.codehaus.jackson.xc Package that contains XML Compatibility functionality for Jackson, such as handlers for JAXB annotations

 

Jackson Mr Bean
org.codehaus.jackson.mrbean Package that implements "interface materializer" functionality, whereby abstract classes and interfaces can be used as-is, and framework constructs implementations as needed.

 

Jackson Smile Format
org.codehaus.jackson.smile Package that contains experimental implementation of "Binary-Encoded JSON-Like" data format handlers (parser, generator, factory produce both, supporting constants).