Annotation Modes

annotationMode controls which serialization annotations are emitted. The same mode applies to all generated types for a schema spec.

Mode	Use when	Main annotations
NONE	You want plain Kotlin models.	None.
KOTLINX_SERIALIZATION	JSON models should use kotlinx.serialization.	@Serializable, @SerialName, contextual serializers.
XMLUTIL	XSD models should round-trip XML with xmlutil.	kotlinx annotations plus @XmlSerialName, @XmlElement, @XmlValue.
JACKSON	Models should serialize with Jackson JSON or Jackson XML.	@JsonProperty, @JsonInclude, Jackson XML annotations.

Null omission

Set omitNulls = true in Jackson mode to emit:

@JsonInclude(JsonInclude.Include.NON_NULL)

For kotlinx.serialization, keep nullable properties defaulted to null and configure the runtime encoder:

val json = Json { encodeDefaults = false }

Numeric enum fallback

Set enumUnknownFallback = true in Jackson mode for integer-valued enums. The generated enum stores a numeric wireValue, annotates it with @JsonValue, and adds a @JsonCreator factory that returns UNKNOWN for unrecognized numeric values.

Kotlinx numeric unknown fallback is not generated yet. String enum wire names still use @SerialName in kotlinx mode.

XML content and attributes

For XSD simple content, xmlutil mode emits @XmlValue on the generated content property and marks attributes with @XmlElement(false). Jackson mode emits the Jackson XML equivalents for XML-sourced models.

Contextual types

BigDecimal, date/time, and duration types need contextual serializers in kotlinx and xmlutil modes. Register serializers in the runtime format as needed for your application.