Java Reference
In-Depth Information
Chapter 4. The Java Persistence API
This chapter deals with the improvements in APIs for communicating with data
sources. Although Java is object oriented, it is designed to handle data of relational
modelsasobjects,whichmightposeaseriousproblembecausethetwoconceptsare
not theoretically compatible. In addition to introducing you to the world of object-rela-
tional mapping, this chapter will show you how to manipulate (create, delete, search,
oredit)thedataofrelationalmodelsasobjectstransparentlyandtransactional.Topics
covered in this chapter are:
• Java Persistence API 2.1
• Java Transaction API 1.2
Java Persistence API 2.1
The Java Persistence API 2.1 Specification was developed under
JSR-338
. This
section just gives you an overview of the improvements in the API. The complete
document specification (for more information) can be downloaded from
http://jcp.org/
JPA (Java Persistence API)
JPA
(
Java Persistence API
) is a Java specification that aims to define the standard
features of
ORM
s (
Object-Relational Mappings
). However, JPA is not a product but
a set of interfaces that require implementations. The most well-known implementa-
tions are as follows:
Hibernate
,
Toplink
,
OpenJPA,
and
EclipseLink
, which is the
reference implementation.
Briefly, we can say that an ORM is an API used to establish a correspondence
between the object model and a relational database. It gives you the ability to handle
the data of your database as if they were objects, without too much worry about the
physical schema.
