A set of database-stored business entities needs to be made accessible.
Database-stored business entities and services need to be exposed to remote clients. However, this could result in a tight coupling between the clients and the business entities, making maintenance or updates difficult. Also, having the database access code mixed with the business code would make the migration to a new database difficult.
• Simplify the interaction with clients external to the subsystem by hiding the complexity of the internal entities.
• Allow looser coupling with the database provider as data retrieval and updates are abstracted via JPA managers.
• Improve maintenance and portability ...