Faceted Project Eclipse environment

Question

Even if I have checked this post and try the solution on it, the problem is still there.

Java compiler level does not match the version of the installed Java project facet. Project-name Unknown Faceted Project Problem (Java Version Mismatch)

Answer 1

Eclipse gives up a solution.
Just click right mouse over the problem, in the Problems view, Choose "Quick Fix", and run with another version which I was running before.