Type Mappings

How Avro types map to JVM types across languages.

Primitive Types

Avro Type	Java	Kotlin	Scala
null	Void	Nothing?	Null
boolean	boolean	Boolean	Boolean
int	int	Int	Int
long	long	Long	Long
float	float	Float	Float
double	double	Double	Double
bytes	byte[]	ByteArray	Array[Byte]
string	String	String	String

Logical Types

Avro Logical Type	Java	Kotlin	Scala
uuid	UUID	UUID	UUID
date	LocalDate	LocalDate	LocalDate
time-millis	LocalTime	LocalTime	LocalTime
time-micros	LocalTime	LocalTime	LocalTime
timestamp-millis	Instant	Instant	Instant
timestamp-micros	Instant	Instant	Instant
local-timestamp-millis	LocalDateTime	LocalDateTime	LocalDateTime
local-timestamp-micros	LocalDateTime	LocalDateTime	LocalDateTime
decimal(p, s)	BigDecimal	BigDecimal	BigDecimal
decimal(p, s) (precise)	DecimalP_S	DecimalP_S	DecimalP_S

Complex Types

Avro Type	Java	Kotlin	Scala
record	record	data class	case class
enum	enum	enum class	enum
array<T>	List<T>	List<T>	List[T]
map<T>	Map<String, T>	Map<String, T>	Map[String, T]
fixed(n)	byte[]	ByteArray	Array[Byte]

Optional Types

Avro Union	Java	Kotlin	Scala
["null", "T"]	Optional<T>	T?	Option[T]
["null", "string"]	Optional<String>	String?	Option[String]
["null", "long"]	Optional<Long>	Long?	Option[Long]

Complex Unions

Avro Union	Generated Type
["string", "int"]	StringOrInt (sealed interface)
["string", "int", "boolean"]	StringOrIntOrBoolean
["null", "string", "int"]	Optional<StringOrInt> / StringOrInt? / Option[StringOrInt]

Wrapper Types

With x-typr-wrapper annotation:

Base Type	Wrapper (Java)	Wrapper (Kotlin)	Wrapper (Scala)
string	record Foo(String value)	value class Foo(val value: String)	opaque type Foo = String
long	record Foo(long value)	value class Foo(val value: Long)	opaque type Foo = Long
uuid	record Foo(UUID value)	value class Foo(val value: UUID)	opaque type Foo = UUID

Records

Feature	Java	Kotlin	Scala
Base type	record	data class	case class
Immutable	Yes	Yes	Yes
Pattern matching	Yes (21+)	Yes	Yes
Copy/wither	withField()	copy()	copy()

Enums

Feature	Java	Kotlin	Scala
Base type	enum	enum class	enum
Ordinal access	ordinal()	ordinal	ordinal
Name access	name()	name	toString

Sealed Interfaces (Multi-Event Topics)

Feature	Java	Kotlin	Scala
Interface	sealed interface	sealed interface	sealed trait
Exhaustive matching	Yes (21+)	Yes	Yes
Permits clause	Explicit	Implicit	Implicit