NPERSISTENCE

Mapping between classes and DB tables has always been a necessity for applications which manipulate and persist data. In the past, each application created its own ORM layer in which the application's specific classes where mapped to specific tables in the DB using custom SQL statements... In order to untie the link between the applications and ORM vendors, the ORM technology had to be standardized - resulting in JPA. JPA offers a set of standard APIs with which an application can meet all its persistence needs.