Mastering Hibernate

Entity

A Hibernate entity is, typically, a sophisticated Plain Old Java Object (POJO). It is sophisticated because it represents a business model whose data is assumed to be persistent. It's always decorated with various annotations, which enable additional characteristics, among other things. Or, it is configured using an hbm Hibernate mapping XML file. When an entity contains other entities, or a collection of other entities, this implies a database association for which you have to declare the proper mapping configuration to define the relationship type.

An entity can also embed other POJOs that are not entities. In such cases, the other entities are considered value objects. They have no identity, and have little business significance on their ...