Here are people who have contributed to Jackson JSON process development:
(version numbers in brackets indicate release in which the problem was fixed)

Tatu Saloranta, tatu.saloranta@iki.fi: Author

Alain Penders:
  * Reported problem with JavaTypeMapper, where floating point numbers were
    accidentally converted to Booleans.
    [0.8]

Mike Eastey:
  * Reported problem with JavaTypeMapper had a bug which prevented custom
    mappers (as well as slower interface-based introspection) from working,
    provided path to specific underlying bugs.
    [0.8.2]

Augusto Callejas
  * Reported problem with JavaTypeMapper (and JsonTypeMapper), which
    caused read operation not to handle EOF appropriately but instead
    cause a NullPointerException.
    [0.9]

Maciej Pestka:
  * JavaTypeMapper did not implicitly flush generator after mapping
    objects: it should, and now will (note: JsonTypeMapper not directly
    affected, flushing still needed)
    [0.9]

Tudor Bosman:
  * Symbol table handling not thread-safe
    [0.9.3]

Michael Mangeng:
  * Suggested [JACKSON-1]: make JsonNode implement Iterable<JsonNode> to
    allow use of Java 5 foreach loop with container nodes.
    [0.9.3]

Johannes Link:
  * Reported [JACKSON-8]: Serialization of BigDecimal broken with JavaTypeMapper
    [0.9.3]