Eclipse IDE - Open Call Hierarchy is empty/broken

I also tried the suggestions above, as well as the hint given here: http://mschrag.blogspot.co.at/2009/01/open-type-cant-find-your-class.html

Nothing worked until today when I found out that I am a donkey... I once configured a filter in the "Call Hierarchy" view and so no entries were shown because filtered out. Once I removed / disabled the filter everything worked fine again.

When you go to the eclipse bug report for this issue, somebody says, you should install over the Market place the Java 12 support.
When I installed it, it was working properly again

The following may help:

• Calling eclipse with eclipse.exe -clean -refresh forces Eclipse to rebuild the index. After that the feature worked again.
• Closing and re-opening the project.