If a @onetomany(cascade = cascadetype.ALL) in class "A" refers to a superclass(abstract or not) of an inheritance hierarchy (class "B") and this superclass have not the relative @manytoone property - in order to map a strong relation from A to B as also described in the ebean manual on page 52) Ebean FAILS to insert the relative "A" foreign keys when it tries to save the B instances( Ebean.save(someAinstance); )
The expected result should be a successful cascade save operation seen that the annotation presents a cascadetype.ALL attribute.
Please note that the expected behaviour is present if instead of a superclass, the @onetomany point to a "normal" class (i.e. either not a superclass or a subclass of some class).
Ebean should provide the expected behaviour and cascade persist all the referenced instances regardless of their nature. (i.e. it should always insert the right foreign keys).