The Enterprise JavaBeans (EJB) 3.0 specification includes an additional persistence specification called the Java Persistence API (JPA). It is an API for creating, removing and querying across lightweight Java objects and can be used both within a compliant EJB 3.0 Container and a standard Java SE 5 environment.
Oracle TopLink is a leader in the JPA community delivering the JPA 1.0 reference implementation with TopLink Essentials and now having developed the JPA 2.0 reference implementation with EclipseLink.
As of Oracle TopLink 11g, TopLink Essentials has been replaced with EclipseLink JPA. EclipseLink JPA implements JPA 1.0 and is responsible for delivering the persistence framework.