The purpose of Hibernate is to relieve the developer from a significant amount of common data persistence-related programming tasks. Hibernate adapts to the developer's development process, whether starting from scratch or from a legacy database.
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 generates the SQL calls and relieves the developer from manual result set handling and object conversion, keeping the application portable to all SQL databases.
Hibernate provides transparent persistence for "Plain Old Java Objects"; the only strict requirement for a persistent class is a no-argument constructor, not compulsorily public. (Proper behavior in some applications also requires special attention to the equals() and hashCode() methods.[1])
Hibernate is typically used both in standalone Java applications and in Java EE applications using servlets or EJB session beans.
