Hibernate is an open source object/relational mapping tool for Java that lets you develop persistent classes and persistent logic without caring how to handle the data. Hibernate not only takes care of the mapping from Java classes to database tables (and from Java data types to SQL data types),but also provides data query and retrieval facilities and can significantly reduce development time otherwise spent with manual data handling in SQL and JDBC. Hibernate's goal is to relieve the developer from 95% of common data persistence related programming tasks.

Hibernate makes it far easier to build robust,high-performance database applications with Java. You only need to write a simple POJO (Plain Old Java Object),create an XML mapping file that describes relationship between the database and the class attributes and call few Hibernate APIs to load/store the persistent objects.