ClasscastException in kubernetes-maven-plugin

[rhierlmeier]

Describe the bug

I run into the following exception with the maven-kubernetes-plugin:

> mvn -e clean install
...
rg.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.eclipse.jkube:kubernetes-maven-plugin:1.11.0:build (docker-build-app) on project kubernetes-sample: A type incompatibility occurred while executing org.eclipse.jkube:kubernetes-maven
-plugin:1.11.0:build: class java.util.HashMap cannot be cast to class java.lang.String (java.util.HashMap and java.lang.String are in module java.base of loader 'bootstrap')
...
Caused by: java.lang.ClassCastException: class java.util.HashMap cannot be cast to class java.lang.String (java.util.HashMap and java.lang.String are in module java.base of loader 'bootstrap')
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.addAsList (MavenConfigurationExtractor.java:73)
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.getElement (MavenConfigurationExtractor.java:54)
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.getElement (MavenConfigurationExtractor.java:59)
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.getElement (MavenConfigurationExtractor.java:59)
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.getElement (MavenConfigurationExtractor.java:59)
    at org.eclipse.jkube.kit.common.util.MavenConfigurationExtractor.extract (MavenConfigurationExtractor.java:41)
    at org.eclipse.jkube.kit.common.util.MavenUtil.getPlugins (MavenUtil.java:73)
    at org.eclipse.jkube.kit.common.util.MavenUtil.convertMavenProjectToJKubeProject (MavenUtil.java:205)
    at org.eclipse.jkube.maven.plugin.mojo.build.AbstractDockerMojo.doExecute (AbstractDockerMojo.java:434)
    at org.eclipse.jkube.maven.plugin.mojo.build.AbstractDockerMojo.execute (AbstractDockerMojo.java:413)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)

Maven-Version:

> mvn -v
Apache Maven 3.8.6 (84538c9988a25aec085021c365c560670ad80f63)
Maven home: C:\ProgrammeDE\Java\tools\apache-maven-3.8.6
Java version: 17.0.4, vendor: Eclipse Adoptium, runtime: C:\ProgrammeDE\Java\jdk17.0.4_8-win64
Default locale: de_DE, platform encoding: Cp1252
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

Eclipse JKube version

1.11.0

Component

Kubernetes Maven Plugin

Apache Maven version

other (please specify in additional context)

Gradle version

None

Steps to reproduce

1. Add the following maven plugin to pom.xml that has also the kubernetes-maven-plugin configured

<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-checkstyle-plugin</artifactId>
        <version>3.2.1</version>
	<configuration>
		<checkstyleRules>
			<module name="Checker">
				<module name="TreeWalker">
					<module name="IllegalImport">
						<property name="severity" value="warning" />
						<property name="illegalPkgs" value="sun, edu"/>
					</module>

					<module name="RedundantImport"/>
				</module>
			</module>
		</checkstyleRules>
		....
	</configuration>
</plugin>

2. Run mvn install

The <module name="RedundantImport"/> causes the exception. When I change it to

<module name="RedundantImport">
     <property name="severity" value="warning" />
</module>

then the exception does no longer occur.

Expected behavior

The configuration of the checkstyle-maven-plugin is a valid Maven configuration.
The kubernetes-maven-plugin should work with such a configuration

Runtime

Kubernetes (vanilla)

Kubernetes API Server version

1.25.3

Environment

Windows

Eclipse JKube Logs

No response

Sample Reproducer Project

No response

Additional context

No response