Hibernate is an object-relational mapping (ORM) library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database. Hibernate solves Object-Relational impedance mismatch problems by replacing direct persistence-related database accesses with high-level object handling functions. The Hibernate 2.1 framework won a Jolt Award in 2005. [1]
Hibernate is free as open source software that is distributed under the GNU Lesser General Public License.
Reference:
http://en.wikipedia.org/wiki/Hibernate_(Java)
