Question

Where do i put my hibernate annotations?

Is it the line above my instance variable? Or before the getter? Or before the setter? Or doesn’t it really matter?

Thanks a lot

Answer 1

You place them either on the field or on the getter. From the Hibernate Annotations Reference Guide:

2.2.1. Marking a POJO as persistent entity

(…)

Depending on whether you annotate
fields or methods, the access type
used by Hibernate will be field or
property. The EJB3 spec requires that
you declare annotations on the element
type that will be accessed, i.e. the
getter method if you use property
access, the field if you use field
access. Mixing annotations in both
fields and methods should be avoided.
Hibernate will guess the access type
from the position of @Id or
@EmbeddedId.

You might also want to read about the @Access annotation that allows to force/override the access type (prior to Hibernate Annotations 3.5 and JPA 2.0, it was part of Hibernate Annotation Extensions):

2.2.2.2. Access type

By default the access type of a class
hierarchy is defined by the position
of the @Id or @EmbeddedId annotations.
If these annotations are on a field,
then only fields are considered for
persistence and the state is accessed
via the field. If there annotations
are on a getter, then only the getters
are considered for persistence and the
state is accessed via the
getter/setter. That works well in
practice and is the recommended
approach.

Note

The placement of annotations within a class hierarchy has to be consistent
(either field or on property) to be
able to determine the default access
type. It is recommended to stick to
one single annotation placement
strategy throughout your whole
application.

However in some situations, you need
to:

• force the access type of the entity hierarchy
• override the access type of a specific entity in the class hierarchy
• override the access type of an embeddable type

The best use case is an embeddable
class used by several entities that
might not use the same access type. In
this case it is better to force the
access type at the embeddable class
level.

(…)

Regarding the pros and cons of both styles, I suggest to read the following questions:

• Hibernate/JPA – annotating bean methods vs fields
• Hibernate Annotations – Which is better, field or property access?
• Performance difference between annotating fields or getter methods in Hibernate / JPA