Do you know that it costs a lot of money to get a Certified Java Programmer' certificate? It could cost you thousands of euros. Let's imagine we will develop a browser-based training system to help people prepare for such a certification exam. A user can request a quiz for the system.

The system picks a set of questions from its database, and compose them together to make a quiz. It rates the user's answers, and gives hints if the user requests it. In addition to users, we also have tutors who provide questions and hints. In addition, examiner who must certify questions to make sure they are not too trivial, and that they are meaningful Make a use case diagram to model this system.