I have a superclass `Questions` and its subclass `MultipleChoiceQuestions`

Superclass has a field `activity`

I want to create a `Set<MultipleChoiceQuestions>` and use `OneToMany` annotation using `mappedBy = "activity"`

e.g.

```
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "activity" )
private Set<NQIMultipleChoiceQuestions> mcqQuestions = new HashSet<NQIMultipleChoiceQuestions>();

```

I am getting this error:

```
org.hibernate.AnnotationException: mappedBy reference an unknown target entity property 

```

However, it works fine if I create a set of superclass entities,

e.g.

```
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "activity")
private Set<NQIQuestions> questions = new HashSet<NQIQuestions>();

```

Is there a way to map to property of superclass?