JDBC: (Java Database connectivity) API offers how a client may connect to a db. http://www.oracle.com/technetwork/java/javase/jdbc/index.html
Entity Beans: It is an Enterprise Bean that represents persistent data maintained in db. An entity bean can manage its own persistent or delegate to the EJB Container. https://docs.oracle.com/cd/A97335_02/apps.102/a83725/entity1.htm
JDO: Java Data Objects API which one of its important feature is transparency of persistence service to the domain model. http://www.oracle.com/technetwork/java/index-jsp-135919.html
JPA: Java Persistence API provides a POJO(Plain Old Java Objects) persistence model for Object-relational mapping. So we write java classes which is not specific to any container or server.http://www.oracle.com/technetwork/java/javaee/tech/persistence-jsp-140049.html
