Javadocs on push with Gitlab Pages with Maven Pipeline in jdk22

Question

I have a Maven project running on jdk22 for which I try to generate JavaDocs on Gitlab with CI/CD.

This is my .gitlab-ci.yml

image: maven:latest

pages:
  stage: deploy
  script:
    - mvn javadoc:aggregate # Generate Javadocs
    - mkdir public          # GitLab Pages requires your site to be in a 'public' directory
    - cp -r target/site/apidocs/* public  # Copy Javadocs to the 'public' directory
  artifacts:
    paths:
      - public
  only:
    - main

This is the relevant part from my pom.xml

...
    <modules>
        <module>core</module>
        <module>shell</module>
        <module>storage</module>
        <module>json</module>
        <module>utility</module>
    </modules>

    <build>
        <sourceDirectory>src</sourceDirectory>
        <testSourceDirectory>tests</testSourceDirectory>

        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <configuration>
                    <source>22</source>
                    <target>22</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <properties>
        <maven.compiler.source>22</maven.compiler.source>
        <maven.compiler.target>22</maven.compiler.target>
    </properties>
...

And this the log from the failed pipeline execution.

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.11.0:compile (default-compile) on project core: Fatal error compiling: error: invalid target release: 22 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

It seems as if the maven compiler plugin has problems with jdk22. Is this version not supported as it is still in early access?

Answer 1

The simple problem here is that at the moment (time of writing this anser) no EA build of JDK 22 simply exist...

Updated:

Some hints. If you already use properties like:

 <properties>
        <maven.compiler.source>22</maven.compiler.source>
        <maven.compiler.target>22</maven.compiler.target>
 </properties>

You don't need to define this:

    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.11.0</version>
            <configuration>
                <source>22</source>
                <target>22</target>
            </configuration>
        </plugin>
    </plugins>

since JDK9+ you should use:

 <properties>
        <maven.compiler.release>21</maven.compiler.release>
 </properties>

Also a plugin should be defined in pluginManagement instead.

Also convention over configuration has a lot of advantages. Every project has the same structure and that makes it easier to understand and to on-board. So I strongly recommend to follow convention-over-configuration. (default directory layout!)