Jackson is a java-based json-processing package that contains:

* high-performance streaming json parser/generator
* tree model that can be built from/written to parser/generator
* object mapper that implements data binding to/from
* parser/generator
api of streaming parser/generator is similar to stax api used for efficient xml processing on java platform.

beyond very fast json parser and generator, jackson project also offers full data binding support through 2 different approaches: "object mapper" for full pojo to/from json data mapping (similar to jaxb2) and "tree mapper" for something similar to dom and xpath.