SerializationFeature
Date: 2016-12-04

com.fasterxml.jackson.databind

## Enum SerializationFeature

- java.lang.Object
- - java.lang.Enum<SerializationFeature>
  - - com.fasterxml.jackson.databind.SerializationFeature

- All Implemented Interfaces:
    ConfigFeature, java.io.Serializable, java.lang.Comparable<SerializationFeature>

      public enum SerializationFeature
      extends java.lang.Enum<SerializationFeature>
      implements ConfigFeature

  Enumeration that defines simple on/off features that affect the way Java objects are serialized.

  Note that features can be set both through `ObjectMapper` (as sort of defaults) and through `ObjectWriter`. In first case these defaults must follow "config-then-use" patterns (i.e. defined once, not changed afterwards); all per-call changes must be done using `ObjectWriter`.

- - ### Enum Constant Summary

    Enum Constants
    Enum Constant and Description
    `CLOSE_CLOSEABLE` Feature that determines whether `close` method of serialized root level objects (ones for which `ObjectMapper`'s writeValue() (or equivalent) method is called) that implement `Closeable` is called after serialization or not.
    `EAGER_SERIALIZER_FETCH` Feature that determines whether `ObjectWriter` should try to eagerly fetch necessary `JsonSerializer` when possible.
    `FAIL_ON_EMPTY_BEANS` Feature that determines what happens when no accessors are found for a type (and there are no annotations to indicate it is meant to be serialized).
    `FAIL_ON_SELF_REFERENCES` Feature that determines what happens when a direct self-reference is detected by a POJO (and no Object Id handling is enabled for it): either a `JsonMappingException` is thrown (if true), or reference is normally processed (false).
    `FAIL_ON_UNWRAPPED_TYPE_IDENTIFIERS` Feature that determines what happens when an object which normally has type information included by Jackson is used in conjunction with `JsonUnwrapped`.
    `FLUSH_AFTER_WRITE_VALUE` Feature that determines whether `JsonGenerator.flush()` is called after `writeValue()` method that takes JsonGenerator as an argument completes (i.e.
    `INDENT_OUTPUT` Feature that allows enabling (or disabling) indentation for the underlying generator, using the default pretty printer configured for `ObjectMapper` (and `ObjectWriter`s created from mapper).
    `ORDER_MAP_ENTRIES_BY_KEYS` Feature that determines whether `Map` entries are first sorted by key before serialization or not: if enabled, additional sorting step is performed if necessary (not necessary for `SortedMap`s), if disabled, no additional sorting is needed.
    `USE_EQUALITY_FOR_OBJECT_ID` Feature that determines whether Object Identity is compared using true JVM-level identity of Object (false); or, `equals()` method.
    `WRAP_EXCEPTIONS` Feature that determines whether Jackson code should catch and wrap `Exception`s (but never `Error`s!) to add additional information about location (within input) of problem or not.
    `WRAP_ROOT_VALUE` Feature that can be enabled to make root value (usually JSON Object but can be any type) wrapped within a single property JSON object, where key as the "root name", as determined by annotation introspector (esp.
    `WRITE_BIGDECIMAL_AS_PLAIN` Deprecated. Since 2.5: use `JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN` instead (using `ObjectWriter.with(com.fasterxml.jackson.core.JsonGenerator.Feature)`).
    `WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS` Feature that determines how type `char[]` is serialized: when enabled, will be serialized as an explict JSON array (with single-character Strings as values); when disabled, defaults to serializing them as Strings (which is more compact).
    `WRITE_DATE_KEYS_AS_TIMESTAMPS` Feature that determines whether `Date`s (and sub-types) used as `Map` keys are serialized as timestamps or not (if not, will be serialized as textual values).
    `WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS` Feature that controls whether numeric timestamp values are to be written using nanosecond timestamps (enabled) or not (disabled); if and only if datatype supports such resolution.
    `WRITE_DATES_AS_TIMESTAMPS` Feature that determines whether Date (and date/time) values (and Date-based things like `Calendar`s) are to be serialized as numeric timestamps (true; the default), or as something else (usually textual representation).
    `WRITE_DATES_WITH_ZONE_ID` Feature that determines whether date/date-time values should be serialized so that they include timezone id, in cases where type itself contains timezone information.
    `WRITE_DURATIONS_AS_TIMESTAMPS` Feature that determines whether time values that represents time periods (durations, periods, ranges) are to be serialized by default using a numeric (true) or textual (false) representations.
    `WRITE_EMPTY_JSON_ARRAYS` Deprecated. Since 2.8 there are better mechanism for specifying filtering; specifically using `JsonInclude` or configuration overrides.
    `WRITE_ENUMS_USING_INDEX` Feature that determines whethere Java Enum values are serialized as numbers (true), or textual values (false).
    `WRITE_ENUMS_USING_TO_STRING` Feature that determines standard serialization mechanism used for Enum values: if enabled, return value of `Enum.toString()` is used; if disabled, return value of `Enum.name()` is used.
    `WRITE_NULL_MAP_VALUES` Feature that determines whether Map entries with null values are to be serialized (true) or not (false).
    `WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED` Feature added for interoperability, to work with oddities of so-called "BadgerFish" convention.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `enabledByDefault()` Accessor for checking whether this feature is enabled by default.
    `boolean` | `enabledIn(int flags)` Convenience method for checking whether feature is enabled in given bitmask
    `int` | `getMask()` Returns bit mask for this feature instance
    `static SerializationFeature` | `valueOf(java.lang.String name)` Returns the enum constant of this type with the specified name.
    `static SerializationFeature[]` | `values()` Returns an array containing the constants of this enum type, in the order they are declared.

    - ### Methods inherited from class java.lang.Enum

      `clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf`

    - ### Methods inherited from class java.lang.Object

      `getClass, notify, notifyAll, wait, wait, wait`

- - ### Enum Constant Detail

    - #### WRAP_ROOT_VALUE

          public static final SerializationFeature WRAP_ROOT_VALUE

      Feature that can be enabled to make root value (usually JSON Object but can be any type) wrapped within a single property JSON object, where key as the "root name", as determined by annotation introspector (esp. for JAXB that uses `@XmlRootElement.name`) or fallback (non-qualified class name). Feature is mostly intended for JAXB compatibility.

      Feature is disabled by default.

    - #### INDENT_OUTPUT

          public static final SerializationFeature INDENT_OUTPUT

      Feature that allows enabling (or disabling) indentation for the underlying generator, using the default pretty printer configured for `ObjectMapper` (and `ObjectWriter`s created from mapper).

      Note that the default pretty printer is only used if no explicit `PrettyPrinter` has been configured for the generator or `ObjectWriter`.

      Feature is disabled by default.

    - #### FAIL_ON_EMPTY_BEANS

          public static final SerializationFeature FAIL_ON_EMPTY_BEANS

      Feature that determines what happens when no accessors are found for a type (and there are no annotations to indicate it is meant to be serialized). If enabled (default), an exception is thrown to indicate these as non-serializable types; if disabled, they are serialized as empty Objects, i.e. without any properties.

      Note that empty types that this feature has only effect on those "empty" beans that do not have any recognized annotations (like `@JsonSerialize`): ones that do have annotations do not result in an exception being thrown.

      Feature is enabled by default.

    - #### FAIL_ON_SELF_REFERENCES

          public static final SerializationFeature FAIL_ON_SELF_REFERENCES

      Feature that determines what happens when a direct self-reference is detected by a POJO (and no Object Id handling is enabled for it): either a `JsonMappingException` is thrown (if true), or reference is normally processed (false).

      Feature is enabled by default.

      Since:
        2.4

    - #### WRAP_EXCEPTIONS

          public static final SerializationFeature WRAP_EXCEPTIONS

      Feature that determines whether Jackson code should catch and wrap `Exception`s (but never `Error`s!) to add additional information about location (within input) of problem or not. If enabled, most exceptions will be caught and re-thrown (exception specifically being that `IOException`s may be passed as is, since they are declared as throwable); this can be convenient both in that all exceptions will be checked and declared, and so there is more contextual information. However, sometimes calling application may just want "raw" unchecked exceptions passed as is.

      Feature is enabled by default.

    - #### FAIL_ON_UNWRAPPED_TYPE_IDENTIFIERS

          public static final SerializationFeature FAIL_ON_UNWRAPPED_TYPE_IDENTIFIERS

      Feature that determines what happens when an object which normally has type information included by Jackson is used in conjunction with `JsonUnwrapped`. In the default (enabled) state, an error will be thrown when an unwrapped object has type information. When disabled, the object will be unwrapped and the type information discarded.

      Feature is enabled by default.

      Since:
        2.4

    - #### CLOSE_CLOSEABLE

          public static final SerializationFeature CLOSE_CLOSEABLE

      Feature that determines whether `close` method of serialized root level objects (ones for which `ObjectMapper`'s writeValue() (or equivalent) method is called) that implement `Closeable` is called after serialization or not. If enabled, close() will be called after serialization completes (whether succesfully, or due to an error manifested by an exception being thrown). You can think of this as sort of "finally" processing.

      NOTE: only affects behavior with root objects, and not other objects reachable from the root object. Put another way, only one call will be made for each 'writeValue' call.

      Feature is disabled by default.

    - #### FLUSH_AFTER_WRITE_VALUE

          public static final SerializationFeature FLUSH_AFTER_WRITE_VALUE

      Feature that determines whether `JsonGenerator.flush()` is called after `writeValue()` method that takes JsonGenerator as an argument completes (i.e. does NOT affect methods that use other destinations); same for methods in `ObjectWriter`. This usually makes sense; but there are cases where flushing should not be forced: for example when underlying stream is compressing and flush() causes compression state to be flushed (which occurs with some compression codecs).

      Feature is enabled by default.

    - #### WRITE_DATES_AS_TIMESTAMPS

          public static final SerializationFeature WRITE_DATES_AS_TIMESTAMPS

      Feature that determines whether Date (and date/time) values (and Date-based things like `Calendar`s) are to be serialized as numeric timestamps (true; the default), or as something else (usually textual representation). If textual representation is used, the actual format is one returned by a call to `MapperConfig.getDateFormat()`: the default setting being `StdDateFormat`, which corresponds to format String of "yyyy-MM-dd'T'HH:mm:ss.SSSZ" (see `DateFormat` for details of format Strings).

      Note: whether this feature affects handling of other date-related types depend on handlers of those types, although ideally they should use this feature

      Note: whether `Map` keys are serialized as Strings or not is controlled using `WRITE_DATE_KEYS_AS_TIMESTAMPS`.

      Feature is enabled by default, so that date/time are by default serialized as timestamps.

    - #### WRITE_DATE_KEYS_AS_TIMESTAMPS

          public static final SerializationFeature WRITE_DATE_KEYS_AS_TIMESTAMPS

      Feature that determines whether `Date`s (and sub-types) used as `Map` keys are serialized as timestamps or not (if not, will be serialized as textual values).

      Default value is 'false', meaning that Date-valued Map keys are serialized as textual (ISO-8601) values.

      Feature is disabled by default.

    - #### WRITE_DATES_WITH_ZONE_ID

          public static final SerializationFeature WRITE_DATES_WITH_ZONE_ID

      Feature that determines whether date/date-time values should be serialized so that they include timezone id, in cases where type itself contains timezone information. Including this information may lead to compatibility issues because ISO-8601 specification does not define formats that include such information.

      If enabled, Timezone id should be included using format specified with Java 8 `DateTimeFormatter#ISO_ZONED_DATE_TIME` definition (for example, '2011-12-03T10:15:30+01:00[Europe/Paris]').

      Note: setting has no relevance if date/time values are serialized as timestamps.

      Feature is disabled by default, so that zone id is NOT included; rather, timezone offset is used for ISO-8601 compatibility (if any timezone information is included in value).

      Since:
        2.6

    - #### WRITE_DURATIONS_AS_TIMESTAMPS

          public static final SerializationFeature WRITE_DURATIONS_AS_TIMESTAMPS

      Feature that determines whether time values that represents time periods (durations, periods, ranges) are to be serialized by default using a numeric (true) or textual (false) representations. Note that numeric representation may mean either simple number, or an array of numbers, depending on type.

      Note: whether `Map` keys are serialized as Strings or not is controlled using `WRITE_DATE_KEYS_AS_TIMESTAMPS`.

      Feature is enabled by default, so that period/duration are by default serialized as timestamps.

      Since:
        2.5

    - #### WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS

          public static final SerializationFeature WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS

      Feature that determines how type `char[]` is serialized: when enabled, will be serialized as an explict JSON array (with single-character Strings as values); when disabled, defaults to serializing them as Strings (which is more compact).

      Feature is disabled by default.

    - #### WRITE_ENUMS_USING_TO_STRING

          public static final SerializationFeature WRITE_ENUMS_USING_TO_STRING

      Feature that determines standard serialization mechanism used for Enum values: if enabled, return value of `Enum.toString()` is used; if disabled, return value of `Enum.name()` is used.

      Note: this feature should usually have same value as `DeserializationFeature.READ_ENUMS_USING_TO_STRING`.

      Feature is disabled by default.

    - #### WRITE_ENUMS_USING_INDEX

          public static final SerializationFeature WRITE_ENUMS_USING_INDEX

      Feature that determines whethere Java Enum values are serialized as numbers (true), or textual values (false). If textual values are used, other settings are also considered. If this feature is enabled, return value of `Enum.ordinal()` (an integer) will be used as the serialization.

      Note that this feature has precedence over `WRITE_ENUMS_USING_TO_STRING`, which is only considered if this feature is set to false.

      Feature is disabled by default.

    - #### WRITE_NULL_MAP_VALUES

          public static final SerializationFeature WRITE_NULL_MAP_VALUES

      Feature that determines whether Map entries with null values are to be serialized (true) or not (false).

      Feature is enabled by default.

    - #### WRITE_EMPTY_JSON_ARRAYS

          @Deprecated
          public static final SerializationFeature WRITE_EMPTY_JSON_ARRAYS

      Deprecated. Since 2.8 there are better mechanism for specifying filtering; specifically using `JsonInclude` or configuration overrides.
      Feature that determines whether Container properties (POJO properties with declared value of Collection or array; i.e. things that produce JSON arrays) that are empty (have no elements) will be serialized as empty JSON arrays (true), or suppressed from output (false).

      Note that this does not change behavior of `Map`s, or "Collection-like" types.

      NOTE: unlike other `SerializationFeature`s, this feature can not be dynamically changed on per-call basis, because its effect is considered during construction of serializers and property handlers.

      Feature is enabled by default.

    - #### WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED

          public static final SerializationFeature WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED

      Feature added for interoperability, to work with oddities of so-called "BadgerFish" convention. Feature determines handling of single element `Collection`s and arrays: if enabled, `Collection`s and arrays that contain exactly one element will be serialized as if that element itself was serialized.

      When enabled, a POJO with array that normally looks like this:

            { "arrayProperty" : [ 1 ] }

      will instead be serialized as

            { "arrayProperty" : 1 }

      Note that this feature is counterpart to `DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY` (that is, usually both are enabled, or neither is).

      Feature is disabled by default, so that no special handling is done.

    - #### WRITE_BIGDECIMAL_AS_PLAIN

          @Deprecated
          public static final SerializationFeature WRITE_BIGDECIMAL_AS_PLAIN

      Deprecated. Since 2.5: use `JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN` instead (using `ObjectWriter.with(com.fasterxml.jackson.core.JsonGenerator.Feature)`).
      Feature that determines whether `BigDecimal` entries are serialized using `BigDecimal.toPlainString()` to prevent values to be written using scientific notation.

      NOTE: since this feature typically requires use of `JsonGenerator.writeNumber(String)` it may cause compatibility problems since not all `JsonGenerator` implementations support such mode of output: usually only text-based formats support it.

      Feature is disabled by default.

    - #### WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS

          public static final SerializationFeature WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS

      Feature that controls whether numeric timestamp values are to be written using nanosecond timestamps (enabled) or not (disabled); if and only if datatype supports such resolution. Only newer datatypes (such as Java8 Date/Time) support such resolution -- older types (pre-Java8 java.util.Date etc) and Joda do not -- and this setting has no effect on such types.

      If disabled, standard millisecond timestamps are assumed. This is the counterpart to `WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS`.

      Feature is enabled by default, to support most accurate time values possible.

      Since:
        2.2

    - #### ORDER_MAP_ENTRIES_BY_KEYS

          public static final SerializationFeature ORDER_MAP_ENTRIES_BY_KEYS

      Feature that determines whether `Map` entries are first sorted by key before serialization or not: if enabled, additional sorting step is performed if necessary (not necessary for `SortedMap`s), if disabled, no additional sorting is needed.

      Feature is disabled by default.

    - #### EAGER_SERIALIZER_FETCH

          public static final SerializationFeature EAGER_SERIALIZER_FETCH

      Feature that determines whether `ObjectWriter` should try to eagerly fetch necessary `JsonSerializer` when possible. This improves performance in cases where similarly configured `ObjectWriter` instance is used multiple times; and should not significantly affect single-use cases.

      Note that there should not be any need to normally disable this feature: only consider that if there are actual perceived problems.

      Feature is enabled by default.

      Since:
        2.1

    - #### USE_EQUALITY_FOR_OBJECT_ID

          public static final SerializationFeature USE_EQUALITY_FOR_OBJECT_ID

      Feature that determines whether Object Identity is compared using true JVM-level identity of Object (false); or, `equals()` method. Latter is sometimes useful when dealing with Database-bound objects with ORM libraries (like Hibernate). Note that Object itself is actually compared, and NOT Object Id; naming of this feature is somewhat confusing, so it is important that Object for which identity is to be preserved are considered equal, above and beyond ids (which are always compared using equality anyway).

      NOTE: due to the way functionality is implemented, it is very important that in addition to overriding `Object.equals(java.lang.Object)` for Objects to match (to be considered "same") it is also necessary to ensure that `Object.hashCode()` is overridden to produce the exact same value for equal instances.

      Feature is disabled by default; meaning that strict identity is used, not `equals()`

      Since:
        2.3

  - ### Method Detail

    - #### values

          public static SerializationFeature[] values()

      Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

          for (SerializationFeature c : SerializationFeature.values())
              System.out.println(c);

      Returns:
        an array containing the constants of this enum type, in the order they are declared

    - #### valueOf

          public static SerializationFeature valueOf(java.lang.String name)

      Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
      Parameters:
        `name` - the name of the enum constant to be returned.
      Returns:
        the enum constant with the specified name
      Throws:
        `java.lang.IllegalArgumentException` - if this enum type has no constant with the specified name
        `java.lang.NullPointerException` - if the argument is null

    - #### enabledByDefault

          public boolean enabledByDefault()

      Description copied from interface: `ConfigFeature`
      Accessor for checking whether this feature is enabled by default.
      Specified by:
        `enabledByDefault` in interface `ConfigFeature`

    - #### getMask

          public int getMask()

      Description copied from interface: `ConfigFeature`
      Returns bit mask for this feature instance
      Specified by:
        `getMask` in interface `ConfigFeature`

    - #### enabledIn

          public boolean enabledIn(int flags)

      Description copied from interface: `ConfigFeature`
      Convenience method for checking whether feature is enabled in given bitmask
      Specified by:
        `enabledIn` in interface `ConfigFeature`