XPages java.util.Comparator cannot be resolved

Question

I'm revisiting an XPages application that was last touched a number of months ago. It was previously built and running fine. In Designer (9.0.1 FP9) I'm now seeing the following errors when the project is cleaned and built.

This application also uses the org.openntf.Utils class. When looking at Java code the following error, along with a couple of others is displayed (although not listed on the Problems tab)

I recently had to delete the workspace folder in the Notes Data directory, so not sure if I've lost config or preference changes that are required. Any pointers much appreciated.

Answer 1

It's likely to be the same root cause as this question, not picking up the right JVM folder Xpages can't load, Error 500; java.util cannot be resolved