Unknown packaging: kjar

[danshome]

Affected version

4.0.0-rc-5

Bug description

The Kie Maven Plugin for Apache Drools doesn't work with Maven 4.

https://github.com/apache/incubator-kie-drools/tree/main/kie-maven-plugin

[ERROR] Unresolvable build extension: Plugin org.kie:kie-maven-plugin:10.1.0 or one of its dependencies could not be resolved:
[ERROR] Failed to read artifact descriptor for org.codehaus.plexus:plexus-component-annotations:jar:1.6: Failed to collect dependencies at org.kie:kie-maven-plugin:jar:10.1.0 -> org.apache.maven.shared:maven-artifact-transfer:jar:0.9.1 -> org.apache.maven:maven-core:jar:3.9.6 -> org.codehaus.plexus:plexus-component-annotations:jar:1.6: The following artifacts could not be resolved: org.codehaus.plexus:plexus-component-annotations:pom:1.6 (absent)
[ERROR] -> [Help 2]
[ERROR] Unknown packaging: kjar @ line 11, column 3

[danshome]

Note that the mvnup didn't detect any problematic plugins or failures in our projects...

mvnup -m 4.1.0 --all check

...

[INFO]
[INFO] Upgrading Maven plugins to recommended versions Summary:
[INFO] 0 POM(s) modified
[INFO] 130 POM(s) needed no changes
[INFO] ✓ Strategy completed successfully
[INFO]
[INFO] Overall Upgrade Summary:
[INFO] 130 POM(s) processed
[INFO] 130 POM(s) modified
[INFO] 0 POM(s) needed no changes
[INFO] 0 error(s) encountered
[INFO]
[INFO] Executed Strategies:
[INFO] • Upgrading POM model version
[INFO] • Applying Maven inference optimizations
[INFO] • Applying Maven 4 compatibility fixes
[INFO] • Upgrading Maven plugins to recommended versions
[INFO] ✓ All upgrades completed successfully!

[khmarbaise]

[ERROR] Unresolvable build extension: Plugin org.kie:kie-maven-plugin:10.1.0 or one of its dependencies could not be resolved:
[ERROR] Failed to read artifact descriptor for org.codehaus.plexus:plexus-component-annotations:jar:1.6: Failed to collect dependencies at org.kie:kie-maven-plugin:jar:10.1.0 -> org.apache.maven.shared:maven-artifact-transfer:jar:0.9.1 -> org.apache.maven:maven-core:jar:3.9.6 -> org.codehaus.plexus:plexus-component-annotations:jar:1.6: The following artifacts could not be resolved: org.codehaus.plexus:plexus-component-annotations:pom:1.6 (absent)

That looks like a problem while downloading the artifacts ? (Using the correct version of kie-maven-plugin?)
I've checked the site https://github.com/apache/incubator-kie-drools/releases the version matches ... Do you use a local repository manager ? Network proxy/firewall ?

Configured the plugin in an example project (using Maven 4.0.0-rc-5)

$> mvn --version                                                                                                                                       1 ↵
Apache Maven 4.0.0-rc-5 (fb3ecaef88106acb40467a450248dfdbd75f3b35)
Maven home: /Users/khm/tools/maven
Java version: 25.0.1, vendor: Oracle Corporation, runtime: /Users/khm/.sdkman/candidates/java/25.0.1-open
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "14.6.1", arch: "aarch64", family: "mac"

and executed it in the life cycle (configured as extensions <packaging>kjar</packaging>)

[INFO] 
[INFO] --- kie:10.1.0:validateDMN (default-validateDMN) @ deep-reflection ---
[INFO] Looking for DMN models in path: /Users/khm/ws-git-soebes/examples/deep-reflection/src/main/resources
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] Total time:  0.912 s
[INFO] Finished at: 2025-12-21T10:29:10+01:00
..

(It fails because it's missing information in the src/main/resources directory... but the download and the execution are fine...