Hibernate Reactive

A reactive API for Hibernate ORM, supporting non-blocking database drivers and a reactive style of interaction with the database.

Hibernate Reactive may be used in any plain Java program, but is especially targeted toward usage in reactive environments like Quarkus and Vert.x.

Currently PostgreSQL, MySQL, MariaDB, Db2, CockroachDB, MS SQL Server and Oracle are supported.

Learn more at http://hibernate.org/reactive.

Compatibility

Hibernate Reactive has been tested with:

• Java 17, 21, 25, 26
• PostgreSQL 18
• MySQL 26
• MariaDB 13
• Db2 12
• CockroachDB v26
• MS SQL Server 2025
• Oracle 23
• Hibernate ORM 8.0
• Vert.x Reactive PostgreSQL Client 5.2
• Vert.x Reactive MySQL Client 5.2
• Vert.x Reactive Db2 Client 5.2
• Vert.x Reactive MS SQL Server Client 5.2
• Vert.x Reactive Oracle Client 5.2
• Quarkus via the Hibernate Reactive extension

The exact version of the libraries and images are in the catalog and in the tooling/docker folder.

Documentation

The Introduction to Hibernate Reactive covers everything you need to know to get started, including:

• setting up a project that uses Hibernate Reactive and the Vert.x reactive SQL client for your database,
• configuring Hibernate Reactive to access your database,
• writing Java code to define the entities of your data model,
• writing reactive data access code using a reactive session, and
• tuning the performance of your program.

We recommend you start there!

The Vert.x and Hibernate Reactive How-to explains how to use Hibernate Reactive in Vert.x.

The Hibernate Reactive with Panache Guide introduces Panache Reactive, an active record-style API based on Hibernate Reactive.

Examples

The directory examples contains several small projects showing different features of Hibernate Reactive:

• CRUD operations using the session
• Native queries and stateless session

Quarkus quickstarts

A collection of quickstarts for Quarkus is available on GitHub:

• Hibernate Reactive with RESTEasy Reactive
• Hibernate Reactive with Panache
• Hibernate Reactive with Vert.x Web Routes

Or you can generate a new Quarkus project that uses the Hibernate Reactive extension and start coding right away.

Examples using JBang

With JBang you can run one of the examples available in the catalog without having to clone the repository or setup the project in the IDE. Once you have downloaded JBang, the list of examples is available via:

jbang alias list hibernate/hibernate-reactive

If you want to run one of the example (in this case the one called example), you can do it with:

jbang example@hibernate/hibernate-reactive

or you can open it in your editor (IntelliJ IDEA in this case) with:

jbang edit --open=idea testcase@hibernate/hibernate-reactive

You can also generate and run a db-specific test. See available templates using: jbang template list

cockroachdb-reproducer = Template for a test with CockroachDB using Junit 4, Vert.x Unit and Testcontainers
db2-reproducer = Template for a test with Db2 using Junit 4, Vert.x Unit and Testcontainers
mariadb-reproducer = Template for a test with MariaDB using Junit 4, Vert.x Unit and Testcontainers
mysql-reproducer = Template for a test with MySQL using Junit 4, Vert.x Unit and Testcontainers
pg-reproducer = Template for a test with PostgreSQL using Junit 4, Vert.x Unit and Testcontainers

Example for PostgreSQL:

• Generate java test from template: jbang init --template=pg-reproducer pgTest.java
• Run the test: jbang pgTest.java

Gradle build

The project is built with Gradle, but you do not need to have Gradle installed on your machine.

Building

To compile this project, navigate to the hibernate-reactive directory, and type:

./gradlew compileJava

To publish Hibernate Reactive to your local Maven repository, run:

./gradlew publishToMavenLocal

Building documentation

To build the API and Reference documentation type:

./gradlew assembleDocumentation

You'll find the generated documentation in the subdirectory release/build/documentation.

open release/build/documentation/reference/html_single/index.html
open release/build/documentation/javadocs/index.html

Running tests

By default, the tests use Testcontainers to automatically manage database instances in Docker containers. The tests will run against PostgreSQL unless you specify a different database using the -Pdb property or use the dedicated task, as shown in the table below.

Database	Command	Dedicated task
PostgreSQL	./gradlew test -Pdb=pg	./gradlew testDbPostgreSQL
MySQL	./gradlew test -Pdb=mysql	./gradlew testDbMySQL
MariaDB	./gradlew test -Pdb=maria	./gradlew testDbMariaDB
DB2	./gradlew test -Pdb=db2	./gradlew testDbDB2
SQL Server	./gradlew test -Pdb=mssql	./gradlew testDbMSSQLServer
Oracle	./gradlew test -Pdb=oracle	./gradlew testDbOracle
CockroachDB	./gradlew test -Pdb=cockroachdb	./gradlew testDbCockroachDB

It's even possible (but not recommended) to run all tests on all available databases:

./gradlew testAll

To run specific tests on all databases, use the standard Gradle --tests flag:

./gradlew testAll --tests="*SessionTest*"

The --tests flag works with all test tasks:

./gradlew test --tests="*SessionTest*"
./gradlew testDbMySQL --tests="DefaultPortTest"
./gradlew testDbPostgreSQL testDbMySQL --tests="*SessionTest*"

By default, the standard output streams are logged only for failed tests. To log them for all tests, add the property -PshowStandardOutput.

By default, only failed tests are logged, followed by a summary of the results. To also log passed and skipped tests, add the property -PshowPassedTest.

There are three ways to start the test database.

Using Testcontainers (default)

By default, the tests use Testcontainers to automatically start database containers. If you have Docker installed, running the tests is really easy - you don't need to create the test databases manually. Just type:

./gradlew test

The above command will start an instance of PostgreSQL in a Docker container. You may specify a different database using one of the commands shown in the table above.

The tests will run faster if you reuse the same containers across multiple test runs. To do this, edit the testcontainers configuration file .testcontainers.properties in your home directory, adding the line testcontainers.reuse.enable=true. (Just create the file if it doesn't already exist.)

If you prefer to test on a database that's not started by Testcontainers, you can use the parameters -PskipTestcontainers.

If you already have PostgreSQL installed

If you already have PostgreSQL installed on your machine, you'll just need to create the test database. From the command line, type the following commands:

psql
create database hreact;
create user hreact with password 'hreact';
grant all privileges on database hreact to hreact;
alter user hreact createdb;

Then run ./gradlew test -PskipTestcontainers from the hibernate-reactive directory.

If you already have MySQL installed

If you have MySQL installed, you can create the test database using the following commands:

mysql -uroot
create database hreact;
create user hreact identified by 'hreact';
grant all on hreact.* to hreact;

Then run ./gradlew test -Pdb=mysql -PskipTestcontainers from the hibernate-reactive directory.

If you have Podman

If you have Podman installed, you can start the test database by following the instructions in podman.md.

Limitations

We're working hard to support the full feature set of Hibernate ORM. At present several minor limitations remain.

• The annotation @org.hibernate.annotations.CollectionId is not yet supported.
• With Db2:
  • Automatic schema update and validation is not supported.
  • @Lob annotation is not supported - See this issue on the vertx-db2-client