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Jackson Release 2.20

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Tatu Saloranta edited this page Aug 29, 2025 · 50 revisions

Jackson Version 2.20 was released on August 28, 2025. One release candidate (2.20.0-rc1) was released prior to final 2.20.0.

This wiki page gives a list of links to all changes (with brief descriptions) that were included, as well as about original plans for bigger changes (and in some cases changes to plans, postponing).

Status

Branch is open for patch releases.

Patches

Documentation

Articles, Blog posts

New Modules

Hibernate 7 support

New datatype module added in jackson-datatype-hibernate:

Changes, compatibility

Compatibility: platform requirements

Android

Same as Jackson 2.19, SDK 26

JDK

Same as Jackson 2.19 (mostly Java 8) except:

  • jackson-annotations now requires Java 8 (no more Java 6 baseline)

Kotlin

Same as Jackson 2.19?

Compatibility: versioning

  • jackson-annotations no longer uses patch number: so we have version 2.20 (instead of 2.19.0 and so on)

Compatibility: datatype modules

Guava

Minimum supported Guava version now 22.0 (from 20.0 with 2.19 and prior) -- see guava#158

Changes, behavior

None

Major focus area(s)

Most wanted Features implemented

  • databind#5152: Support "iPhone" style capitalized properties (add MapperFeature.FIX_FIELD_NAME_UPPER_CASE_PREFIX)

Full Change list

Changes, core

Annotations

  • #291: Add optional property for @JacksonInject to allow optionally injected values
  • #293: Improve duplicate Id with different associated object error message
  • #294: Drop patch number from version for 2.20 and later (no more 2.20.0)
  • #296: Drop Java 6 compatibility for 2.20 (Java 8 baseline)

Streaming

  • #1438: ParserBase.close() does not clear _currToken
  • #1441: Add StreamReadFeature.CLEAR_CURRENT_TOKEN_ON_CLOSE (default: true)
  • #1448: Upgrade FastDoubleParser to 2.0.1
  • #1462: Deprecate URL-taking factory method of JsonFactory

Databind

  • #2678: @JacksonInject added to property overrides value from the JSON even if useInput is OptBoolean.TRUE
  • #2692: Should never call set() on setterless property during deserialization
  • #3072: Allow specifying @JacksonInject does not fail when there's no corresponding value
  • #4136: Drop deprecated (in 2.12) PropertyNamingStrategy implementations from 2.20
  • #4218: If @JacksonInject is specified for field and deserialized by the Creator, the inject process will be executed twice
  • #4656: DeserializationProblemHandler.handleUnexpectedToken() cast Object to String
  • #5103: Use writeStartObject(Object forValue, int size) for ObjectNode serialization
  • #5151: Add new exception type, MissingInjectValueException, to be used for failed @JacksonInject
  • #5152: Support "iPhone" style capitalized properties (add MapperFeature.FIX_FIELD_NAME_UPPER_CASE_PREFIX)
  • #5192: Record types are broken on Android when using R8
  • #5194: Custom Throwable not serializable if using JsonAutoDetect settings that only detect Fields
  • #5197: Add more informative exception for back-references with record type
  • #5237: Failing @JsonMerge with a custom Map with a @JsonCreator constructor
  • #5238: Immutable classes with @JsonIdentityInfo can be deserialized; records cannot
  • #5242: Support "binary vectors": @JsonFormat(shape = Shape.BINARY) for float[], double[]
  • #5257: Deprecate URL-taking readValue() methods in ObjectMapper, ObjectReader
  • #5271: EnumDeserializer fails to deserialize Enums with @JsonValue - uses table with name() key instead of @JsonValue key

Changes, data formats

CBOR

  • #137: Allow exposing CBOR "undefined" value as JsonToken.VALUE_EMBEDDED_OBJECT (with embedded value of null)
  • #431: Negative BigInteger values not encoded/decoded correctly
  • #587: Allow exposing CBOR Simple values as JsonToken.VALUE_EMBEDDED_OBJECT with a feature flag
  • #603: Add support for writing unsigned numbers to CBOR

CSV

  • #497: UTF8Reader throws "Need to move partially decoded character; buffer not modifiable" when read only one chinese char
    • NOTE: actual fix already merged in 2.19.0, marked as fixed in 2.20.0
  • #564: CsvParser.getNumberValue(), related, do not throw exception for non-numeric tokens

TOML

  • #497: UTF8Reader throws "Need to move partially decoded character; buffer not modifiable" when read only one chinese char
    • NOTE: TOML part fixed in 2.20, CSV part earlier (in 2.19.0)

XML

  • 768: FromXmlParser lacks extension point for passing custom XmlTokenStream

YAML

  • #497: UTF8Reader throws "Need to move partially decoded character; buffer not modifiable" when read only one chinese char
    • NOTE: YAML part fixed in 2.20, CSV part earlier (in 2.19.0)

Changes, data types

Guava

  • #158: Increase minimum supported Guava from 20.x to 22.x for Jackson 2.20

Hibernate

  • #184: Add jackson-datatype-hibernate7 module for Hibernate version 7
  • #186: Update hibernate 6 code to avoid deprecated code

Joda

  • #92: DateTime serialization result is not same as Java 8 ZonedDateTime
  • #146: DateTime can't be serialized with its own zone (WRITE_DATES_WITH_CONTEXT_TIME_ZONE not respected)

Changes, JVM Languages

Kotlin

  • #967: Kotlin has been upgraded to 2.0.21.
  • #969: Deprecated content has been cleaned up with the version upgrade.
  • #1018: Improved handling of value class has improved performance for both serialization and deserialization.
  • #1020: Exceptions thrown by the old StrictNullChecks are now the similar to the new StrictNullChecks.This means that the old StrictNullChecks will no longer throw MissingKotlinParameterException.
  • #1025: When a null is entered for a non-null parameter, the KotlinInvalidNullException is now thrown instead of the deprecated MissingKotlinParameterException. The new exception is a subclass of InvalidNullException. See #617 for information contained in this exception

Scala

  • #758: Deprecate methods that take URL inputs

Changes, other

Jackson-jr

  • #196: float[] and double[] are serialized to JSON as { }
  • #200: Odd errors when attempting to read byte[] from regular JSON array
  • #201: Support for OffsetDateTime and ZonedDateTime in jackson-jr-extension-javatime
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