Chapter 2. Dependency management

A specific Camel Extensions for Quarkus release is supposed to work only with a specific Quarkus release.

The easiest and most straightforward way to get the dependency versions right in a new project is to use one of the Quarkus tools:

These tools allow you to select extensions and scaffold a new Maven project.

The generated pom.xml will look similar to the following:

<project>
  ...
  <properties>
    <quarkus.platform.artifact-id>quarkus-bom</quarkus.platform.artifact-id>
    <quarkus.platform.group-id>com.redhat.quarkus.platform</quarkus.platform.group-id>
    <quarkus.platform.version>
        <!-- The latest 2.2.x version from https://maven.repository.redhat.com/ga/com/redhat/quarkus/platform/quarkus-bom -->
    </quarkus.platform.version>
    ...
  </properties>
  <dependencyManagement>
    <dependencies>
      <!-- The BOMs managing the dependency versions -->
      <dependency>
        <groupId>${quarkus.platform.group-id}</groupId>
        <artifactId>quarkus-bom</artifactId>
        <version>${quarkus.platform.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
      <dependency>
        <groupId>${quarkus.platform.group-id}</groupId>
        <artifactId>quarkus-camel-bom</artifactId>
        <version>${quarkus.platform.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <!-- The extensions you chose in the project generator tool -->
    <dependency>
      <groupId>org.apache.camel.quarkus</groupId>
      <artifactId>camel-quarkus-sql</artifactId>
      <!-- No explicit version required here and below -->
    </dependency>
    ...
  </dependencies>
  ...
</project>

BOM stands for "Bill of Materials" - it is a pom.xml whose main purpose is to manage the versions of artifacts so that end users importing the BOM in their projects do not need to care which particular versions of the artifacts are supposed to work together. In other words, having a BOM imported in the <depependencyManagement> section of your pom.xml allows you to avoid specifying versions for the dependencies managed by the given BOM.

The particular BOMs that are contained in the pom.xml depend on the extensions that you select using the generator tools which are configured to select a minimal set of consistent BOMs.

If you choose to add an extension at a later point that is not managed by any of the BOMs in your pom.xml file, you do not need to search for the appropriate BOM manually. With the quarkus-maven-plugin you can select the extension, and the tool adds the appropriate BOM as required. You can also use the quarkus-maven-plugin to upgrade the BOM versions.

The com.redhat.quarkus.platform BOMs are aligned with each other which means that if an artifact is managed in more than one BOM, it is always managed with the same version. This has the advantage that application developers do not need to care for the compatibility of the individual artifacts that may come from various independent projects.