# Interface AdditionalData

All Superinterfaces:
  `Serializable`

@Incubating public interface AdditionalData extends Serializable
Marker interface for additional data that can be attached to a `Problem`.

This is effectively a sealed interface that is used to restrict the types of additional data that can be attached to a problem.

Since:
  8.13
See Also:
  - `ProblemSpec.additionalData(Class, Action)`