What is it?
Hibernate is one of the most popular Java Persistence API (JPA) implementations and also one of the most popular Java Object Relational Mapping (ORM) frameworks in general. It helps you to map the classes of your domain model to database tables and automatically generate SQL statements to update the database on object state transitions. That is a complex task, but Hibernate makes it look easy.
You just annotate your domain classes, and Hibernate takes care of the rest. Or, it at least seems like that in the beginning. When you’ve used Hibernate for a while, you begin to recognize that you need to do more than just add an @Entity annotation to your domain model classes. Real-world applications often require advanced mappings, complex queries, custom data types, and caching.