Maven Javadoc Plugin fails to resolve the dependencies that are inherited by all sub-modules in the parent pom file and the dependencies specific to some sub-modules if and only if it's used with Java 11 whereas it works flawlessly with Java 8. This bug is reproducible with this project:
Enter "mvn site" and you'll get the following error message:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.7.1:site (default-site) on project ardor3d: Error generating maven-javadoc-plugin:3.1.1:aggregate report: [ERROR] Exit code: 1 - Ardor3D/ardor3d-swt/src/test/java/com/ardor3d/input/swt/TestSwtMouseWrapper.java:23: error: package org.eclipse.swt.events does not exist
Note that "mvn install" works with Java 11, this problem of dependency management only occurs while generating the Java API documentation with Java 11.