To get a better understanding of the existing devices and their capabilities within OpenEMS, I’d love to have a UML class diagram. My naive hypothesis is, that there must be a software I can simply point to the OpenEMS source code dir and get a nice diagram, showing the classes, inheritances, and maybe even offering the possibility to show/hide the attributes and methods.
I did find Eclipse Papyrus | projects.eclipse.org and its java reverse · Wiki · Eclipse Projects / papyrus / org.eclipse.papyrus-designer · GitLab function, but fail to import more than one package at a time manually and also cannot get the relationships between classes shown.
I also came across the online service of GitHub - 5rijan/UML-diagram-generator: Web application that converts Java source code into UML diagrams. It uses Streamlit for the backend and UI, PlantUML to convert the text to the image, and a Java parser to parse the Java code to PlantUML syntax. and its origin GitHub - mirajp1/java2plantuml: Convert Java source code to PlantUML sytax for UML diagram generation to parse the java classes. But both fail to parse some classes (see respective bug reports).
To not waste any more time in searching, did someone find a solution already and can give me a hint? 
Thx! Simon