Following are the key components of persistence API in EJB:
-
Entity - A persistent object representing the data-store record. It is good to be serializable.
-
EntityManager - Persistence interface to do data operations like add/delete/update/find on persistent object(entity). It also helps to execute queries using Query interface.
-
Persistence unit (persistence.xml) - Persistence unit describes the properties of persistence mechanism.
-
Data Source (*ds.xml) - Data Source describes the data-store related properties like connection url. user-name,password etc.
