Dear students,
The problem I encoutered seems to be related to a known bug in Glassfish when using JEE8 and JSF2.3.
Probably the easiest way to get arround (especially since JSF is just an accessory tool for us) is to use JEE 7 (when you create your project and when importing the libraries). Everything works for me when I do so.
At the end of the first section on the web page
(https://arche.univ-lorraine.fr/course/view.php?id=314#section-1)
you have a very simple application using beans.
Best regards,
Horatiu Cirstea