This article was published at the wishlist below, about JPA 2.0:

1. Restriction in callback methods.
2. @ManyToOne, @OneToMany and @ElementCollection implicits.
3. Converters.
4. Method in EntityManagerFactory for obtaining the list of all entities.
5. Composite keys without key class.
6. UUID as GeneratedType for @GeneratedValue.
7. Default fetch value for @ManyToOne.
8. @ElementCollection.
9. Qualified properties in @OrderBy.

Source: GUJ