使用Jadiru Joda / Hibernate持久用户类型时的AbstractMethodError

I've introduced a "created" column to my user's database of MySQL TIMESTAMP type. I'm attempting to map this to a Joda LocalDateTime using Jadiru's UserType Hibernate mappers. I'm using v2.0 of the UserType classes and I've tried with v 3.6.0 and 3.6.7 of Hibernate. I'm using JDK 1.6. This data access layer is being used as part of a Spring 3 web application. I've introduced a "created" column to my user's