Java

The following options are configurable with JsonConfig:

• bidirectional serialization, supports Maps, Collections, arrays (primitives, multidimensional), beans, DynaBeans, Enums & Annotations (jdk15 package only)
• supports custom serialization with 3 schemes:
  • the bean implements JSONString interface
  • register a JsonBeanProcessor for the whole bean
  • register a JsonValueProcessor for a bean property (key and/or type)
• register a DefaultValueProcessor for returning a default value when a null reference is encountered
• plugin your own strategy for selecting a JsonBeanProcessor with JsonBeanProcessorMatcher
• plugin your own strategy for selecting a DefaultValueProcessor with DefaultValueProcessorMatcher
• modify the target property name when transforming from JSON to Java if the name is not a valid JavaIdentifier
• skip modifying map keys when transforming form JSON to Java if the key is not a valid JavaIdentifier
• register your own JavaIdentifierTransformer strategy
• plugin your own strategy for setting properties into a bean when transforming from JSON to Java thanks to PropertySetStrategy
• publish events when building a JSONObject or JSONarray. The available events are:
  • object start/end
  • array start/end
  • propertySet
  • elementAdded
  • warning (recoverable)
  • error (exception)
• Cycle detection, there are two default strategies (default throws an exception), you can register your own
• Skip transient fields when serailizing to JSON (default=don't skip)
• Skip JAP @Transient annotated methods when serailizing to JSON (default=don't skip)
• Exclude bean properties and/or map keys when serailizing to JSON (default=['class','metaClass','declaringClass'])
• Filters provide a finer detail for excluding/including properties when serializing to JSON or transforming back to Java
• plugin your own strategy for instatiating beans if they do now follow the no-args constructor rule
• default JavaBean instantiton strategy accepts package protected and private no-args constructor (Hibernate friendly)
• JSONObject implements java.util.Map and java.util.Comparable
• JSONArray implements java.util.List and java.util.Comparable
• JSONObject, JSONArray and JSONNull implement a base interface: JSON
• JSONAssert, a test-friendly class for testing JSON values

XML

The following options are configurable in XMLSerializer:

• [read] trim leading and trailing whitespace from element values
• [read] skip namespace handling
• [read] trim namespace prefixes
• [write] skip reading type hints (useful for converting back to JSON)
• [write] write type hints (useful for converting back to JSON)
• [write] skip writing type hints (useful for converting back to JSON)
• [write] change default values for Object, Array and Element tag names
• [write] change default value for Root element tag name
• [write] raise error if namespace uri is missing
• [write] transform an explicit array into an implicit array

Web

The following options are configurable in WebUtils:

• do not output quotes for object keys when its safe for JavaScript
• two default strategies for preventing javascript hijacking, you can register your own

Groovy

• support for the leftshift ( << ) operator in JSONObject
• support for the spaceship ( <=> ) and its cousins
• type conversion with the as keyword
• a Groovy JSON builder

JRuby

• JSONArray.empty? is an alias for JSONArray.isEmpty()
• JSONObject.empty? is an alias for JSONObject.isEmpty()
• support for the leftshift ( << ) operator in JSONObject