Jackson Version 2.17 was released on March 12, 2024. One release candidate (2.17.0-rc1) was released prior to final 2.17.0.

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

Branch is open for development.

• 2.17.1 (not yet released)

A skeletal extension, jackson-jr-extension-javatime was added with initial support for just java.time.LocalDateTime: the main goal is to have a place to add support for new types via contributions. To use it, just register extension and support is enabled:

    JSON json = JSON.builder()
        .register(new JacksonJrJavaTimeExtension())
        .build();
    String jsonString = json.asString(new ValueWithTime()); 

Same as Jackson 2.16

In 2.17, JSON Strings like "07" (leading zeroes) will no longer be recognized as coercible numbers for things like Enum indexes.

• #437: Adds DeserializationFeature.FAIL_ON_UNEXPECTED_VIEW_PROPERTIES, enabling of which starts failing known properties that are not part of the active view

Was Not Started Yet (same old story...) during 2.17 development.

• #242: Allow @JsonAnySetter on ElementType.PARAMETER (for use on constructor parameters)

• #507: Add JsonWriteFeature.ESCAPE_FORWARD_SLASHES to allow escaping of '/' for String values
• #1117: Change default RecylerPool implementation to newLockFreePool (from threadLocalPool)
• #1137: Improve detection of "is a NaN" to only consider explicit cases, not double overflow/underflow
• #1145: JsonPointer.appendProperty(String) does not escape the property name
• #1149: Add JsonParser.getNumberTypeFP()
• #1157: Use fast parser (FDP) for large BigDecimals (500+ chars)
• #1169: ArrayIndexOutOfBoundsException for specific invalid content, with Reader-based parser
• #1173: JsonLocation consistently off by one character for many invalid JSON parsing cases
• #1179: Allow configuring DefaultPrettyPrinter separators for empty Arrays and Objects
• #1186: BufferRecycler should avoid setting replacement if one already returned, bigger
• #1195: Use BufferRecycler provided by output (OutputStream, Writer) object if available
• #1202: Add RecyclerPool.clear() method for dropping all recycled instances
• #1203: Faster division by 1000
• #1207: JsonFactory.setStreamReadConstraints(StreamReadConstraints) fails to update "maxNameLength" for symbol tables
• #1217: Optimize char comparison using bitwise OR
• #1218: Simplify Unicode surrogate pair conversion for generation

• #437: Support throwing MismatchedInputException when deserializing properties that are not part of the view
• #736: MapperFeature.REQUIRE_SETTERS_FOR_GETTERS has no effect
• #2543: Introspection includes delegating ctor's only parameter as a property in BeanDescription
• #4160: Deprecate DefaultTyping.EVERYTHING in 2.x and remove in 3.0
• #4194: Add JsonNodeFeature.FAIL_ON_NAN_TO_BIG_DECIMAL_COERCION option to fail on attempting to coerce NaN into BigDecimal
• #4205: Consider types in sun.* package(s) to be JDK (platform) types for purposes of handling
• #4209: Make BeanDeserializerModifier/BeanSerializerModifier implement java.io.Serializable
• #4214: EnumSet deserialization does not work when we activate default typing in ObjectMapper
• #4248: ThrowableDeserializer does not handle null well for cause
• #4250: Add input validation for NumberDeserializers deserializers for "stringified" FP numbers
• #4262: Improve handling of null insertion failure for TreeSet
• #4263: Change ObjectArrayDeserializer to use "generic" type parameter (java.lang.Object) to remove co-variant return type
• #4299: Some Collection and Map fallbacks don't work in GraalVM native image
• #4327: @JsonAlias not respected by polymorphic deduction
• #4337: AtomicReference serializer does not support @JsonSerialize(contentConverter=...)
• #4364: @JsonProperty and equivalents should merge with AnnotationIntrospectorPair
• #4394: Better Base64 support for java.util.UUIDs
• #4403: Deserialization of unknown value for enums does not yield default enum value
• #4416: Deprecate JsonNode.asText(String)

• #449: IndexOutOfBoundsException in JacksonAvroParserImpl for invalid input

• #451: IndexOutOfBoundsException in CBORParser for invalid input
• #458: Unexpected NullPointerException in CBORParser
• #464: Unexpected ArrayIndexOutOfBoundsException in CBORParser for corrupt String value

• #45: Allow skipping ending line break (CsvGenerator.Feature.WRITE_LINEFEED_AFTER_LAST_ROW)

• #251: Unable to deserialize Object with unknown Timestamp field
• #417: IonReader classes contain assert statement which could throw unexpected AssertionError
• #420: IndexOutOfBoundsException thrown by IonReader implementations are not handled
• #424: IonReader throws NullPointerException for unchecked invalid data
• #428: IonParser.getIntValue() fails or does not handle value overflow checks
• #432: More methods from IonReader could throw an unexpected AssertionError
• #434: Unexpected NullPointerException thrown from IonParser::getNumberType()
• #437: IonReader.next() throws NPEs for some invalid content
• #469: IonReader.newBytes() throwing NegativeArraySizeException
• #471: IonReader throws AssertionError for Timestamp value
• #473: IonReader.next() throws ArrayIndexOutOfBoundsException for some corrupt content
• #473: Upgrade ion-java to 1.11.2 and remove handling of exceptions that are no longer leaked

• #462: ProtobufParser.currentName() returns wrong value at root level

• #426: SmileParser throws unexpected IOOBE for corrupt content

• #324: Support use of xsi:type for polymorphic serialization (ToXmlGenerator.Feature.AUTO_DETECT_XSI_TYPE)
• #618: ArrayIndexOutOfBoundsException thrown for invalid ending XML string when using JDK default Stax XML parser
• #631: Add XmlMapper.createGenerator(XMLStreamWriter) and XmlMapper.createParser(XMLStreamReader) overloads
• #634: Support use of xsi:type for polymorphic deserialization (FromXmlParser.Feature.AUTO_DETECT_XSI_TYPE)
• #637: JacksonXmlAnnotationIntrospector.findNamespace() should properly merge namespace information
• #643: XML serialization of floating-point infinity is incompatible with JAXB and XML Schema

• #454: Unexpected NumberFormatException in YAMLParser
• #456: Support max Read/Write nesting depth limits (StreamReadConstraints/ StreamWriteConstraints) for YAML
• #465: YAML: consider starting # and ending : as quotable characters

• #274: Add 1-based Month[De]serializer enabled with JavaTimeFeature.ONE_BASED_MONTHS option

• #294: Optional deserialization, serialization ignore contentConverter

• #118: Support @JsonFormat(shape=STRING) on Range<T>
• #124: Some deserializers throw unexpected NullPointerException when handling invalid input
• #136: Fix for failing Guava Optional test
• #138: GuavaCollectionDeserializer still throws NPE in some circumstances
• #140: Cache deserialization fails with NPE for null valued entries
• #142: RangeSet deserializer fails for content nulls with NPE

• #727: Fixed overriding findCreatorAnnotation instead of hasCreatorAnnotation
• #732: SequenceSerializer removed
• #738: JacksonInject is now preferred over the default argument (fixes #722)
• #740: Reduce conversion cache from Executable to KFunction. This will reduce memory usage efficiency and total memory consumption, but may result in a minor performance degradation in use cases where a large number of factory functions are used as JsonCreator.
• #741: Changed to allow KotlinFeature to be set in the function that registers a KotlinModule. The jacksonObjectMapper {} and registerKotlinModule {} lambdas allow configuration for KotlinModule
• #742: Minor performance improvements to NullToEmptyCollection/Map
• #743: The handling of deserialization using vararg arguments has been improved to allow deserialization even when the input to the vararg argument is undefined. In addition, vararg arguments are now reported as non-required
• #744: Functions that were already marked as deprecated, such as the primary constructor in KotlinModule and some functions in Builder, are scheduled for removal in 2.18 and their DeprecationLevel has been raised to Error. Hidden constructors that were left in for compatibility are also marked for removal. This PR also adds a hidden no-argument constructor to facilitate initialization from reflection.
• #745: Modified isKotlinClass determination method
• #746: The KotlinModule#serialVersionUID is set to private
• #747: Improved performance related to KotlinModule initialization and setupModule. With this change, the KotlinModule initialization error when using Kotlin 1.4 or lower has been eliminated
• #751: KotlinModule#useKotlinPropertyNameForGetter property was deprecated because it differed from the name of the KotlinFeature
• #755: Changes in constructor invocation and argument management. This change degrades performance in cases where the constructor is called without default arguments, but improves performance in other cases
• #758: Deprecated SingletonSupport and related properties to be consistent with KotlinFeature.SingletonSupport
• #760: Caching is now applied to the entire parameter parsing process on Kotlin
• #768: Added value class deserialization support

• #501: make Scala3 enum support part of DefaultScalaModule - and no longer require users to load a separate module
• #666: Support deserialization of TreeSeqMap

No changes to JAX-RS or Jakarta-RS providers.

• #7: Support deserialization of int[]
• #25: Add support for single-int Constructors
• #51: Duplicate key detection does not work for (simple) Trees
• #78: Deserializes "null" to "0.0" for java.lang.Double (wrapper)
• #93: Skip serialization of groovy.lang.MetaClass values to avoid StackOverflowError
• #94: Support for serializing Java Records
• #100: Add support for java.time (Java 8 date/time) types
• #112: overrideStandardValueWriter only applied to first java.nio.file.Path valued field of bean
• #116: Add read/write support for java.nio.file.Path
• #131: Add mechanism for JacksonJrExtensions to access state of JSON.Features