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, excluding annotations that directly depend on Mapper classes.
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 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.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.ser Contains implementation classes of serialization part of data binding.
org.codehaus.jackson.map.type Concrete JavaType implementations.
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.