Hibernate

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.

http://en.wikipedia.org/wiki/Hibernate_(Java)

Learn HQL becomes funny :

• http://demo.wavemaker.com/HQL_Guru/

Hibernate provides a way to display statistic about active Session.

Documentation performance topic

More details are available from API :

Statistics API

French Guide about optimization and setup :

http://arodrigues.developpez.com/tutoriels/java/performance/hibernate-performance-part1-strategies-chargement

JDBC versus Hibernate

• http://code.google.com/p/simple-hibernate-benchmark/

• http://community.jboss.org/wiki/HibernateFAQ-TipsandTricks
• http://community.jboss.org/wiki/HibernateFAQ-PerformanceQA