unable to use umldoclet - Unanticipated error generating UML

[wumpz]

With some older version this worked, at least I could generate some of those diagrams. However, within my actual project I get

[loading /modules/java.desktop/javax/swing/SwingConstants.class]
[loading /modules/java.desktop/javax/swing/ScrollPaneConstants.class]
[loading /modules/java.desktop/javax/swing/text/JTextComponent.class]
error: Unanticipated error generating UML: java.lang.IllegalArgumentException
[done in 1199 ms]
1 error
Command line was: cmd.exe /X /D /C ""C:\Program Files\Eclipse Adoptium\jdk-17.0.8.7-hotspot\bin\javadoc.exe" -J-Xmx2048m -J-Duser.language= -J-Duser.country= @options @packages"

Refer to the generated Javadoc files in 'xxx\apidocs' dir.

Since this seems to be the most generic Exception while generating UML diagrams, I have no clue, whats wrong.

How can I configure javadoc to show me this UML doclet exception + stacktrace.

If I start the generated javadoc.bat manually I get the same exception.

---

JDK 17 (Temurin), umldoclet 2.2

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <configuration>
          <!-- *START* UML generation -->
          <doclet>nl.talsmasoftware.umldoclet.UMLDoclet</doclet>
          <docletArtifact>
            <groupId>nl.talsmasoftware</groupId>
            <artifactId>umldoclet</artifactId>
            <version>2.2.0</version>
          </docletArtifact>
          <additionalOptions>
            <!-- <additionalOption>- -create-puml-files</additionalOption> -->
            <additionalOption>--uml-custom-directive='!pragma layout smetana'</additionalOption>
          </additionalOptions>
          <!-- *END* UML generation -->
          <!-- <useStandardDocletOptions>true</useStandardDocletOptions> -->
          <failOnError>false</failOnError>
          <maxmemory>2g</maxmemory>
          <verbose>true</verbose>
          <doclint>none</doclint>
          <failOnError>false</failOnError>
        </configuration>
        <reportSets>
          <reportSet>
            <id>default</id>
            <reports>
              <report>javadoc</report>
            </reports>
          </reportSet>
        </reportSets>
      </plugin>