Jackson Release: 1.6
(code name: Smiley Bean)
Jackson 1.6 was released on September 6th 2010, about 6 months after 1.5.
It is classified as a "minor" update over 1.5, since it will be mostly backwards compatible (hence not a "major" version bump), but will introduce new features (hence not a "patch" release).
This release had ambitious goals for extending functionality into new areas: both with respect to kinds of use cases supported (bean materialization, ability to update ("merge") existing objects), data types ("Smile" binary format) and third party libraries (parent/child relationship support for ORM. But additionally it significantly improved existing functionality, so that working with Java Enums is more convenient; support for generic types is even more powerful; and JSON Tree Model support is more convenient.
Following is the list of functionality that was implemented for this release.
Implemented features: major
JACKSON-41: Add support for Materialized Beans: ability to generate classes that implement interfaces (and abstract classes) for deserialization, in cases where no other mappings exist.
JACKSON-235: Handle bi-directional references using declarative method(s) (especially useful/important for ORM like Hibernate, iBatis)
JACKSON-264: Ability to "update" values; to read and bind JSON content as properties of existing beans. This is done by using ObjectMapper.updatingReader()" (and reader.readValue(source) on resulting reader object)
JACKSON-331: Add support for Smile (binary JSON) format; used with new SmileFactory (a sub-type of JsonFactory to use with Smile format)
Implemented features: minor
JACKSON-210: Add methods in JsonNode for finding values of named property
JACKSON-212: Allow using Enum.toString() as external serialization instead of Enum.value()
JACKSON-257: Allow registering subtypes for polymorphic type handling (using ObjectMapper.registerSubtypes()).
JACKSON-261: @JsonView now implies that the associated thing is a property (regardless of its visibility), to reduce amount of annotations needed when exposing non-public fields.
JACKSON-282: Add SerializationConfig.Feature.CLOSE_CLOSEABLE to force calling value.close() on serialization. Meaning that if you want to have automatic resource cleanup for root-level values objects, it is easy to enable.
JACKSON-287: Add JsonParser.releaseBufferedContent() for pushing back buffered but unused content, usually after parsing all content of interest (but not necessarily whole stream).
JACKSON-292: Add @JsonAnyGetter to allow convenient serialization of properties bound using @JsonAnySetter (on deserialization).
JACKSON-300: JsonParser.Feature.ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER to make parser accept any all possible backslash-escapes.
JACKSON-302: Add JsonNode.has() for more convenient checking of whether JSON Object or Array node has specified property or element.
JACKSON-316: Add SerializationConfig.Feature.WRITE_NULL_MAP_VALUES, for suppressing writing of null-valued Map entries.
Planned but deferred features
Following features were considered for inclusion, but deferred due to time constraints
JACKSON-163: Add ser/deser feature for ObjectMapper to allow "wrapped" output (mostly for JAXB compatibility)