Hibernate Annotations

Hibernate, like all other object/relational mapping tools, requires metadata that governs the transformation of
data from one representation to the other. In Hibernate 2.x mapping metadata is most of the time declared in
XML text files. Alternatively XDoclet can be used utilizing Javadoc source code annotations together with a
compile time preprocessor.
The same kind of annotation support is now available in the standard JDK, although more powerful and with
better tools support. IntelliJ IDEA and Eclipse for example, support auto-completion and syntax highlighting of
JDK 5.0 annotations which are compiled into the bytecode and read at runtime using reflection. No external
XML files are needed.
The EJB3 specification recognizes the interest and the success of the transparent object/relational mapping
paradigm. It standardizes the basic APIs and the metadata needed for any object/relational persistence mechan-
ism. Hibernate EntityManager implements the programming interfaces and lifecycle rules as defined by the
EJB3 persistence specification and together with Hibernate Annotations offers a complete (and standalone)
EJB3 persistence solution on top of the mature Hibernate core. You may use a combination of all three togeth-
er, annotations without EJB3 programming interfaces and lifecycle, or even pure native Hibernate, depending
on the business and technical needs of your project. At all times you cann fall back to Hibernate native APIs, or
if required, even to native JDBC and SQL.
This release of Hibernate Annotations is based on the final release of the EJB 3.0 / JPA specification (aka JSR-
220 [http://jcp.org/en/jsr/detail?id=220]) and supports all its features (including the optional ones). Hibernate
specific features and extensions are also available through unstandardized, Hibernate specific annotations.
While the Hibernate feature coverage is high, some can not yet be expressed via annotations. The eventual goal
is to cover all of them. See the JIRA road map section for more informations.
If you are moving from previous Hibernate Annotations versions, please have a look at Java Persistence migra- tion guide [http://www.hibernate.org/398.html].
download here