Eclipse doesn't see file even it was in the package

Question

I have worked on a project in Java Spring and using Eclipse, I met this weird thing 2 days ago, everything run ok and it suddenly corrupted.

In Project Explorer the "java" and "resources" folders exist, but in Package Explorer, they don't show. Eclipse knew that "java" and "resources" as package, but it didn't see the file below, and it caused a thousand of errors because of this. Almost of errors were "Some class cannot be resolved". See the images below:

I have tried many ways: clean, rebuild, re-import, restart eclipse, switch workspace, re-checkout the project in another place, download another eclipse but it is still the same. Does anyone know how to solve this thing?

Answer 1

But this is completly normal. You got those dirs included as "sources" and "resources" in Package Explorer - both are threated as "sources" so they are included in Eclipse's build path. This is completly normal - in Package Explorer dirs already included as sources are ommited from file tree. Your problem must be something else. Project clean should help indeed. Try to maven clean as well.