2.8.0 update mapping problem with javax.persistence.OneToMany

Hi Guys.

Hopefully this is the last of my little problems as I upgrade to work with
2.8.0. I changed:

@OneToMany{val mappedBy="parentObject", val
targetEntity=classOf[ChildObject]}
var models: Set[ChildObject] = new HashSet[ChildObject]

Here we are using java.util.Set and java.util.HashSet to keep a list of
child objects against a parent object.

I updated the annotation to work with 2.8.0:

@OneToMany(mappedBy="parentObject", targetEntity=classOf[ChildObject])
var models: Set[ChildObject] = new HashSet[ChildObject]

and now I am getting the following Hibernate error:

Caused by: org.hibernate.MappingException: Could not determine type for:
java.util.Set, at table: PARENT_OBJECT, for columns:
[org.hibernate.mapping.Column(models)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:269)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:253)
at org.hibernate.mapping.Property.isValid(Property.java:185)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:440)
at org.hibernate.mapping.RootClass.validate(RootClass.java:192)
at org.hibernate.cfg.Configuration.validate(Configuration.java:1108)
at
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1293)
at
org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)

I am not sure how I need to update my annotation to express this
relationship, or if it is some other part of upgrading to 2.8.0 that I am
missing.

Thanks in advance for your help,