The individual CascadeType descriptions can be a bit confusing, but there’s an easy way to figure it out from the general case.
For any of the CascadeType values, it means that if operation X is called on an instance using the EntityManager interface, and that instance has references to other entity instances, and that association has CascadeType.X defined, then the EntityManager operation will also be applied to that associated entity.
So EntityManager.refresh() is defined as :
Refresh the state of the instance from
the database, overwriting changes made
to the entity, if any.
So if entity A has a reference to entity B, and that reference is annotated with @CascadeType.REFRESH, and EntityManager.refresh(A) is called, then EntityManager.refresh(B) is implicitly called also.