In One Minute : Hibernate

Hibernate is the umbrella for a collection of libraries, most notably Hibernate ORM which provides Object/Relational Mapping for java domain objects.
In addition to its own "native" API, Hibernate ORM is also an implementation of the Java Persistence API (jpa) specification.

Hibernate's primary feature is mapping from Java classes to database tables, and mapping from Java data types to SQL data types. Hibernate also provides data query and retrieval facilities. It generates SQL calls and relieves the developer from the manual handling and object conversion of the result set.

The mapping of Java classes to database tables is implemented by the configuration of an XML file or by using Java Annotations. When using an XML file, Hibernate can generate skeleton source code for the persistence classes. This is auxiliary when annotations are used. Hibernate can use the XML file or the Java annotations to maintain the database schema.

Resources

• Official website - Downloads, Tutorials, Documentation, Community, ...
• Hibernate Wikipedia Article
• Vlad Mihalcea's Tutorials
• Hibernate DZone Examples - Step-by-step Hibernate Examples / Tutorials for beginners.

Books

• Java Persistence with Hibernate
• High-Performance Java Persistence