Release 1.5 - 04 March 2019

** General **

  • Multiple bug fixes and improvements in core Genson and the Scala module
  • Introduction of a new Bundle for Java Date and Time API, contributed in this PR
  • Genson is OSGI compliant, see


  • Starting with release 1.5 Genson requires Java 8+


  • Starting with release 1.5, Scala 2.10 is no longer supported. Genson is cross built for Scala 2.11 ans 2.12

Release 1.4 - 27 March 2016


  • Fix #86 - Class metadata was generated twice when used with UntypedConverter
  • Fix #83 - Case insensitive enums
  • Fix #79 - Merge annotations from the same class and from super class/interfaces
  • Fix #69 - Introduce the notion of aliases for JsonProperty
  • Fix #81 - Add the ability to filter properties defined at runtime
  • Custom default values for null
  • Make failing on null when a primitive is expected configurable
  • Fix #75 - Allow to serialize special floating point numbers, disabled by default
  • Fix #78 - Replace usePermissiveParsing with independent configuration options
  • Fix #62 - Escape quotes & slashes inside json object keys
  • Allow to use a specific classloader instead of the default one PR #72
  • Fix “ClassCastException with generics and Integer as generic type” by ignoring bridge methods


  • Fix issue #73 - Configure a list of ignored root types for ser/de


  • Fix #82 - null and missing values are deserialized as None instead of null for Options
  • Allow to use a specific classloader instead of the default one PR #72

Release 1.3 - 12 April 2015


  • Issue #49 - Wrap/Unwrap root values in an enclosing object
  • Issue #51 - Deserialize single value as list
  • Issue #50 - Improved deserializeValues usability
  • Issue #45 - Genson annotations overriding Jaxb annotations
  • Allowing user config to override bundle config
  • Fix issue #53 - NPE in ASMCreatorParameterNameResolver
  • Issue #41 - Accept to deserialize timestamps and string dates
  • Issue #36 - Automatic encoding detection (UTF-8/16/32)
  • Fixes #38 - Ser/de single byte as int instead of base64 encoded string


  • Issue #52 - Supporting releases for multiple scala versions (2.10 and 2.11) using std versioning scheme.


  • Issue #40 - Converters for LocalDate, LocalDateTime and LocalTime
  • Default serialization of dates as timestamp - WARN might introduce regression in user code
  • Issue #16 - Supporting JsonDateFormat annotation with Jodatime (Mutable)DateTime types


  • Support XmlRootElement annotation as part of Issue #49
  • Issue #46 - Improved use when mixing XmlAdapter and XmlElement


  • New configuration system, making it easier to customize Genson in Jax-RS apps
  • Issue #42, #39 - Support for disabling/enabling Genson in any Jax-RS apps

Jsr 353 - Jsonp

  • Issue #36 - Automatic encoding detection (UTF-8/16/32)

Release 1.2 - 26 December 2014


  • Issue #24 - Automatic discovery of Genson with Jersey v2
  • Issue #26 - Iterate over sequential root json values not enclosed in an array, enabled via usePermissiveParsing
  • Issue #28 - Avoiding NPE with Resteasy when an exception is being thrown
  • Issue #30 - Handle primitive short and float
  • Issue #31 - Handle primitive and boxed single byte and char

Genson Scala

  • Handling erased primitive types in generics, requires scala 2.11

Release 1.1 - 22 September 2014

“Medium” release providing new extensions, configuration and bug fixes. The API remains backwards compatible.

Genson core

  • Issue #4 Ads deserializeInto method in Genson, allowing to deserialize in an exisintg Pojo
  • Issue #13 Ads failOnMissingProperty option allowing to throw an exception when no property
  • Issue #17 Ads useClassMetadataWithStaticType option allowing to ser or not object type when it is the same the static type. in the class matches with the on in the json.
  • Issue #12 Avoiding to pick converters from cache when a contextual converter is available
  • Issue #11 Accessors/Mutators/Creator Properties annotations are merged together


  • Adding support for json4s AST via the new bundle Json4SBundle
  • Fixes a bug in the ScalaBundle when serializing to a byte array
  • Issue #19 Handling correctly root arrays in ScalaBundle
  • Issue #10 ScalaBundle: Ser/de of None without parameter type was failing

Release 1.0 - 27 June 2014

Major release and migration to GitHub with a complete new website.

  • Fresh new website
  • Scala extension & Bundle
  • Jodatime Bundle
  • Guava Bundle (only Optional for now)
  • Converters for TreeSet, TreeMap, LinkedList, LinkedHashSet, LinkedHashMap, ArrayDeque, PriorityQueue, boxed float and short
  • Moving Genson.Builder to a new class GensonBuilder in its own file. Renaming some configuration methods
  • New writeString(name, value), writeNumber(name, value)… methods in ObjectWriter
  • Deser. to java.util.List instead of array when no type information is available
  • Minor bug fixes

Release 0.99 - 13 April 2014

This release introduces some new features, the main being JSR 353 and some simplifications of code related to exceptions. Indeed all checked exceptions have been replaced by unchecked ones.

  • Complete implementation of JSR 353
  • Removing TransformationRuntimeException and TransformationException, removing also IOException from signatures. Replaced previous exceptions with the new JsonBindingException. Gensons uses now only unchecked exceptions
  • Guava Bundle, at the moment only Optional is supported
  • Adding ability to ser/deser byte array as array of ints instead of base 64 encoded strings
  • Supporting line & block comments in json
  • Bug fix: #issue 6, fixing memory leak with tomcat (and probably websphere & cie too)
  • Bug fix: serialization of byte array from Pojos, key was not being serialized.
  • Bug fix: using class classloader in ASM resolver instead of Gensons classloader

Release 0.98 - 7 August 2013

  • JSR 353 types support via a new bundle JSR353Bundle
  • Bugfix in JsonReader skipValue method
  • Bugfix when using BeanViews, introduced after some refactoring in version 0.95

Release 0.97 - 11 June 2013

  • Bugfix: Jersey messagebodywriter does not close outputstream anymore. Previously they were being closed by inadvertance, streams should be closed by the code that is managing them, not the code that reads/writes.

Release 0.96 - 2 June 2013

  • Important [ bug fix] related to generics getting mixed up in internal cache, you are highly encouraged to upgrade to 0.96.

Release 0.95 - 21 May 2013

  • JAXB annotations and types support, enabled by default for JAX-RS implementations.
  • Added Resteay integration (works as for Jersey, just drop the jar :)).
  • Addition of a bundle system, now users can group a set of custom features or configuration into a bundle and register all at once.
  • Support for serialization and deserialization of byte arrays (encoded by genson to base64).
  • Addition of contextual factory mechanism, allowing to define specific behaviour based on property info (name, annotations, etc).
  • New annotations: @JsonDateFormat and @JsonConverter, can be used on Pojo properties to define a specific date format and converter to use (while still using the default ones for the rest of the properties).
  • Improved map ser/deser to handle all sort of keys. Map with complex keys can now be serialized and deserialized back (however they are not represented as a json object but an array of objects).
  • Bug fix: Generic self referencing types.

Release 0.94 - 5 February 2013

  • corrected bug related to generics and default generic converter
  • added pretty printing support (enable it via the Genson.Builder)
  • replaced IllegalStateExceptions from JsonReader with JsonStreamException (having location information row/col, package visibility only for this version)
  • added UUID, Calendar, Set converters, ability to use dates/calendars as timeinmillis, unit testing, TypeUtil clean code remove unused method and ParameterizedTypeImpl, we already have ExtendedParameterizedType
  • tests for JsonReader column/row location in Exceptions, added type safe methods to Context and depracted old ones + test
  • improved spring mvc integration
  • ValueType.OBJECT type has been replaced with Map (as unknown object types are deserialized to maps)
  • ValueType.INTEGER type has been replaced with long. INTEGER meaning here a numeric value with no decimals.
  • More unit testing, code enhancements and internal stuff.

Release 0.93 - 1 October 2012

  • Added new methods to Genson.Builder allowing to filter and rename properties of classes without using annotations and requiring only small code
  • Corrected bugs related to generics
  • Replaced double parsing algorithm with a more accurate one
  • Added the possibility to choose whether to use custom double parsing algorithm (very fast) or standard Double.parse (exact)
  • Metadata bug corrected for attributes defined as Object.

Release 0.92 - 27 August 2012

  • Jersey integration with automatic detection (and working with DI frameworks)
  • Spring web integration
  • Enhanced filtering support and provided better user customization
  • Default converters for URI, BigInteger, BigDecimal, Timestamp.

Release 0.91 - 20 August 2012

  • Addition of factory methods in Genson class allowing to ease the creation of ObjectReader/Writer.

Release 0.9 - 12 August 2012

  • First stable release.