Hibernate (framework): Difference between revisions

Revision as of 23:31, 8 June 2023

Revision as of 04:25, 9 June 2023

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==Persistence==

Hibernate provides transparent persistence for [[Plain Old Java Object]]s (POJOs).{{sfn|Bauer|King|Gregory|2016}}{{rp|§=3.2.2|pp=37-38}} The only strict requirement for a persistent class is a [[Nullary constructor|no-argument constructor]],{{sfn|Bauer|King|Gregory|2016}}{{rp|§=3.2.3|pp=39}}, though not necessarily {{code|public}}. Proper behavior in some applications also requires special attention to the {{code|equals()}} and {{code|hashCode()}} methods in the object classes.<ref>{{cite web|title=Equals and HashCode|url=https://community.jboss.org/wiki/EqualsAndHashCode|publisher=JBoss Community}}</ref> Hibernate recommends providing an identifier attribute, and this is planned to be a mandatory requirement in a future release.<ref>{{cite web|title=Hibernate User Guide: 2.5.5. Provide identifier attribute|url=http://docs.jboss.org/hibernate/orm/5.2/userguide/html_single/Hibernate_User_Guide.html#entity-pojo-identifier|publisher=JBoss Community}}</ref>

Collections of data objects are typically stored in Java collection classes, such as implementations of the {{code|Set}} and {{code|List}} interfaces. [[Generics in Java|Java generics]], introduced in Java 5, are also supported. Hibernate can be configured to [[lazy load]] associated collections.{{sfn|Bauer|King|Gregory|2016}}{{rp|§=12.1|pp=289-293}} Lazy loading is the default as of Hibernate 3.