Hibernate is most widely used ORM tool for Java (at least by the time I am writing this). It has lot’s of Awesome feature and tricks to manage Entities,
Implicit Inheritance is one of them. You can use a parent to fetch some entity and it will load it’s some entities.

Key: Every entity is a subclass of Object class. If you create criteria for Object class you will get all the entities data.

Session session = factory.openSession();   
List l=session.createCriteria(Object.class).list();   
for (Object object : l) {    
 System.out.println("Object: "+l);