How to create a Jandex index in Quarkus for classes in a external module

Quarkus automatically indexes the main module but, when you have additional modules containing CDI beans, entities, objects serialized as JSON, you need to explicitly index them.

There are a couple of different (easy to implement) options to do so.

Using the Jandex Maven plugin

Just add the following to the additional module pom.xml:

<build>
  <plugins>
    <plugin>
      <groupId>org.jboss.jandex</groupId>
      <artifactId>jandex-maven-plugin</artifactId>
      <version>1.2.2</version>
      <executions>
        <execution>
          <id>make-index</id>
          <goals>
            <goal>jandex</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

It’s the most beneficial option if your dependency is external to your project and you want to build the index once and for all.

Using the Gradle Jandex plugin

If you are using Gradle, there is a third party plugin allowing to generate a Jandex index: https://github.com/kordamp/jandex-gradle-plugin .

Adding an empty META-INF/beans.xml

If you add an empty META-INF/beans.xml file in the additional module src/main/resources, the classes will also be indexed.

The classes will be indexed by Quarkus itself.

Indexing other dependencies

If you can’t modify the dependency (think of a third-party dependency, for instance), you can still index it by adding an entry to your application.properties:

quarkus.index-dependency.<name>.group-id=
quarkus.index-dependency.<name>.artifact-id=
quarkus.index-dependency.<name>.classifier=(this one is optional)

with <name> being a name you choose to identify your dependency.