What is fastjson
Fastjson is a JSON processor (JSON parser + JSON generator) written in Java:
FAST (measured to be faster than any other Java parser and databinder, incudes jackson. )
Powerful (full data binding for common JDK classes as well as any Java Bean class, Collection, Map, Date or enum)
Zero-dependency (doest not rely on other packages beyond JDK)
Open Source (Apache License 2.0)