Questions tagged [ebean]

Ebean is an open source Object Relational Mapping tool.

It's goal is to provide a simpler alternative to JPA (Java Persistence API) implementations such as Hibernate and Eclipselink.

It does this by providing a “sessionless” API and a simpler query language. That means:

• No Session Object (or UnitOfWork or EntityManager)
• No Attached or Detached Beans
• No merge(), persist(), flush(), or clear(). Instead Ebean has save() and delete()

Ebean, just like JPA has a Persistence Context but has some architectural differences to allow it to have a different approach to the entity bean lifecycle and removing the need to manage EntityManagers.

Why Ebean? ... why different from JPA?

Ebean uses the JPA Mapping annotations and will follow those very closely.

However, Ebean has been architected and built from a different perspective than JPA. The Architectural and Query language differences are reasonably fundamental to both Ebean and JPA so its hard to see these differences going away anytime soon.

JPA is architected to use an “EntityManager” which closely matches a Hibernate “Session” and a Toplink “UnitOfWork”. This brings with it the concepts that an entity bean can be attached or detached from the EntityManager (with associated merge, flush clear operations etc). If the EntityManager is used across multiple Transactions the EntityManager needs to be managed typically by a EJB Session Bean, Seam, Spring or similar container/framework.

Ebean is architected to not require an EntityManager (or Session or UnitOfWork object) with the goal of making it easier to use and to remove the requirement to manage EntityManager objects (Aka a different approach to Lifecycle management).

Although Ebean doesn't have a EntityManager it DOES have a “Persistence Context” (like JPA) and by default in Ebean the persistence context is transaction scoped and automatically managed.