I was mapping a Java 5 enum to a database column in a JPA-annotated Hibernate class today and almost created a UserType (ugh!). Then I remembered that it’s much easier! You can just use @Enumerated to convert between the enum’s toString() and a text (varchar, text, etc.) column transparently. There’s also support for more complex types which I have not had a chance to explore. The usage looks like this:

@Entity
public class MyClass {
     ...
     @Enumerated(EnumType.STRING)
     private MyEnum myCol;
     ...
}

See the JPA docs for a full example.