JPA Objects does not support enumerated types, because Naked Objects itself does not support enumerated types. The JPA @Enumerated and @EnumType annotations may therefore not be used.

A good workaround is to use regular immutable ("reference data") entities, annotated with the Naked Objects' @Bounded annotation. @Bounded here means that there is a bounded, finite, set of instances; you'll find that Naked Objects viewers will provide drop-down list boxes for these classes.