In this chapter, we covered the advanced areas of JPA, which are usually a necessity in professional software development. Certainly, there are many institutions that rely on stored procedures, and so we learnt how JPA 2.1 could invoke those predefined functions and retrieve a result set as an entity or non-entity. We saw how to supply Parameter.Mode for those procedure parameters , which have input and output modes: IN, OUT, INOUT, or REF_CURSOR.

We can now write entity associations that are a type of java.util.Map. The annotation that helps us is @MapKey. There are variants such as @MayKeyColumn and @MapKeyJoinColumn that gives us, the application developer, more control of object-relational mapping.

We journeyed onwards to Criteria API and bulk updates and deletes. This is a new feature of JPA 2.1. On this path of performance efficiency, we saw how entity graphs allow us to control entities and how their dependent sub-graphs of entities can be fetched. Finally, we reviewed miscellaneous updates to the specification including the downcasting of super entities to sub-entities in inheritance relationships.

The final chapter of this book will look to the future: Java EE 8 and cloud computing. I encourage you to go online, download the Online Chapter, Moving Java EE.next to the Cloud from the link http://www.packtpub.com/sites/default/files/downloads/7942EN_Chapter_12_Moving_Java_EE_next_to_the_cloud.pdf.