I found the fix, it was on the link you provided. I did not need to change the lib to libs but instead needed to do the following:

To export the references: simply go to “Properties > Java Build Path > Order and Export”, and check all the references you want exported.

Thanks!

I am having the exact same issue, same errors. I tried making the changes suggested in the link provided (changing lib folder to libs and cleaning), still getting same errors.