Hibernate ORM

Hibernate makes relational data visible to a program written in Java, in a natural and type-safe form,

Hibernate is the most successful ORM solution ever, in any programming language.

Right alongside its own "native" API, Hibernate provides an implementation of the Jakarta Persistence specification. In fact, the first version of JPA was inspired by the success of Hibernate 2, and Hibernate was the major influence on the specification and API.

Thus, Hibernate can be easily used in any environment supporting JPA: Java SE standalone applications, EE servers like WildFly, and other containers including Quarkus.

The project motto is: relational persistence for idiomatic Java.

Hibernate lets you write persistent classes following natural object-oriented idioms including inheritance and polymorphism, representing associations using standard Java collections. Hibernate does not require a persistent class to implement an interface, extend a base class, or depend on any other intrusive framework-specific API.

Information about object/relational mappings may be provided by annotating the persistent class with annotations defined by Jakarta Persistence, or by supplying mappings in XML.

Hibernate provides flexible data fetching strategies, and an extremely-tunable two-level caching architecture. For managing concurrent data access, Hibernate defaults to optimistic locking with automatic versioning or time-stamping, but pessimistic locks may be explicitly requested. Most SQL is generated at system initialization time instead of at runtime.

Hibernate consistently achieves superior performance compared to hand-written JDBC code, in both runtime efficiency and developer productivity. Importantly, Hibernate makes it much easier to tune the performance of code after it’s written.

From its very birth more than two decades ago, Hibernate was designed specifically for use in highly concurrent environments and in server clusters. Since then, its architecture has been proven via heavy production usage in innumerable enterprise systems covering every major industry, and by its acceptance among hundreds of thousands of Java developers across more than two decades.

Hibernate Query Language (HQL) is an incredibly powerful object-oriented dialect of SQL, with almost every feature of ANSI SQL SELECT statements you’ve ever heard of. Arguably, it supports more of ANSI SQL than most relational databases.

Since Hibernate Processor has access to your entities and their mapping annotations at compilation time, it’s able to completely validate the syntax and typing of a HQL query when you compile your Java code. Hibernate Tools and IntelliJ IDEA even provide automatic code completion and validation for HQL queries as you type.

If all else fails, Hibernate lets you write your own SQL queries in the native dialect of your database.

Hibernate is tested every day on PostgreSQL, MySQL, Db2, Oracle, SQL Server, Sybase ASE, EDB, TiDB, MariaDB, HANA, CockroachDB, H2, and HSQLDB. There’s even built-in support for Spanner.

The Community Dialects module defines compatibility with a range of older databases, including Informix, Ingres, and Teradata, along with incubating support for SQLite.

Adoption of Hibernate was originally driven by grassroots Java developers looking for a way out of the quagmire of handwritten object/relational mapping code, in-house ORM frameworks, and failed industry standards like entity beans. Later, Hibernate was the first major Java development tool to move from XML to annotations—​at a time when other frameworks were still promoting the heavy use of XML for just about any task—​and this was a critical step in improving the productivity of Java enterprise development as a whole.

The most recent major versions of Hibernate have placed a central focus on improved error reporting and compile-time type safety, leading to a great improvement in developer experience. This work has driven changes in the latest generation of Jakarta specifications, and in particular lead to the new programming model in Jakarta Data.