I'll be attending Desert Code Camp tomorrow (today). The event will be going from about 9 to like 4:30pm. I'm going to be presenting on Spring Data JPA. Just a volunteer thing. Anyway, I built a presentation here using Prezi.com. Its a pretty sweet service. I also threw together a bit of a demo and posted it on github. Its nothing much, but contains a working example of using Spring Data JPA with general repos along with Specifications. Check it out.
Stop creating a method for every query permutation. Specifications wrap the JPA Criteria API. Using them makes your code less - and then more - readable and reusable. Check them out.
If you don't like the ugliness that is implementing individual specifications, Querydsl based Specifications make everything better.
Do yourself a favor and read this article: Springsource Blog: Advanced Spring Data JPA Specifications and Querydsl
Hey, make sure to annotate child model classes with @PrimaryKeyJoinColumn when using InheritanceType.JOINED. This annotation allows you to specify the column names to be used in mapping parent child relationships.
Additional reading:
Its important to note that using this inheritance model requires an extra join operation when retrieving entities. This may negatively impact performance if running high volume or with anything other than trivial inheritance models.