Can't open project as maven project in eclipse
With a new fork of pf4j the project will not properly open when using eclipse 2018-09 (4.9.0). The .classpath files seem not to be compatible to a multi-module maven project
The procedure in https://stackoverflow.com/a/46012075/1497139 needs to be followed. It would be good to update the documentation accordingly.
Still the p4j module is not handled correctly. The issues seems to be that it has the same name as the main java project and that is not allowd in Eclipse. renaming the main directory from p4j to p4jmaster fixes the issue. You might want to give a hint in the documentation
Thanks! I don't use Eclipse so I don't know too much about Eclipse.
It's the same with Visual Studio Code.
You are always getting the following error message:

So you wont get full IntelliSense feature.
@WolfgangFahl I think we can close this issue. Your comments are helpful and the steps described in comments are straightforward.
It will be useful to have a new section Eclipse in Developers (or few words in the existed How to build section) that would contain all this information, but I don't use Eclipse and I cannot validate the steps.