Java persistent API is a specification and set of interfaces that helps with persistence of java objects into the database. It has been created after success of object relational mapping frameworks - the most popular is Hibernate.
JPA defines standard basic set of features that every object relational mapping framework should have. Almost all current O/R frameworks implement JPA specification. Of course, most of them have additional features to set them apart.
Saving/loading data with JPA is easier, faster and less error prone than writing SQL and mapping query results to objects. However, JPA does not free you from relational database understanding. And while you do not have to write SQL anymore, you have to learn JPQL which is very similar.
JPA defines standard basic set of features that every object relational mapping framework should have. Almost all current O/R frameworks implement JPA specification. Of course, most of them have additional features to set them apart.
Saving/loading data with JPA is easier, faster and less error prone than writing SQL and mapping query results to objects. However, JPA does not free you from relational database understanding. And while you do not have to write SQL anymore, you have to learn JPQL which is very similar.
