Hibernate is an Object/Relational Mapping solution for Java environments. Object-relational mapping or ORM is the programming technique to map application domain model objects to the relational database tables. Hibernate is a java based ORM tool that provides a framework for mapping application domain objects to the relational database tables and vice versa.
For example, the below diagram shows a Hibernate Object Relational Mapping between Student Java class and student table in the database.
Hibernate provides a reference implementation of Java Persistence API, which makes it a great choice as an ORM tool with the benefits of loose coupling.