`jlink` not working with Java 24/25 without `*.jmod` files.

[dansiviter]

Eclipse Temurin 24/25 JDK images do not contain jmod files (see here) due to JEP 493. Therefore, image generation fails with:

[ERROR] Failed to execute goal io.helidon.build-tools:helidon-maven-plugin:4.0.23:jlink-image (jlink-image) on project nucleus-api: Image generation error: The required *.jmod files (e.g. jmods/java.base.jmod) are missing in this JDK: /opt/java/openjdk -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal io.helidon.build-tools:helidon-maven-plugin:4.0.23:jlink-image (jlink-image) on project nucleus-api: Image generation error
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:333)
    ...at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:201)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:361)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:314)
Caused by: org.apache.maven.plugin.MojoExecutionException: Image generation error
    at io.helidon.build.maven.JLinkImageMojo.execute (JLinkImageMojo.java:152)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    ...
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:314)
Caused by: java.lang.IllegalArgumentException: The required *.jmod files (e.g. jmods/java.base.jmod) are missing in this JDK: /opt/java/openjdk
    at io.helidon.build.linker.util.JavaRuntime.assertJdk (JavaRuntime.java:157)
    at io.helidon.build.linker.util.JavaRuntime.current (JavaRuntime.java:182)
    at io.helidon.build.linker.Configuration$Builder.build (Configuration.java:508)
    at io.helidon.build.maven.JLinkImageMojo.execute (JLinkImageMojo.java:149)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)

For workaround is detailed in blog link above but downloading jmod files into the JDK.

[dansiviter]

Further clarification, I'm using Helidon SE 4.2.7, building the image using maven:3.9-eclipse-temurin-25-alpine image. I upgraded the helidon-maven-plugin to 4.0.23 to ensure this wasn't fixed in latest.

[barchetta]

I have reproduced. A quick look at the code indicates that we should be able to remove this check and the requirement for jmod files.

We missed this because the Oracle JDK builds contain the jmod files.

[talios]

Any updates on resolving this at all @barchetta ?