Groovy JSON support and the Boon JSON parser are up to 3x to 5x faster than Jackson at parsing JSON from String and char, and 2x to 4x faster at parsing byte.
Groovy JSON support and Boon JSON support are also faster than Jackson at encoding JSON strings. Boon is faster than Jackson at serializing/de-serializing Java instances to/fro JSON. The core of the Boon JSON parser has been forked into Groovy 2.3 (now in Beta). In the process Boon JSON support was improved and further enhanced. Groovy and Boon JSON parsers speeds are equivalent. Groovy now has the fastest JSON parser on the JVM.