I've recently came across this question and I'm just curious if my work is correct, and if not, where I made a mistake.
My Task:
a) Officials are appointed on a temporary or permanent basis. Professors are civil servants who may be appointed for a fixed term or for life. Professors are also either teaching professors or heads of study. Employees of a scientific institute are civil servants or employees. Professors are subordinate to the Minister of Science, employees of the scientific institute are subordinate to the professors. Both professors and employees of the scientific institute work at the scientific institute. The institute can call meetings with professors and staff.
Create the appropriate UML Class Diagram.
My answer:
b) A professor can inform the secretariat that he or she would like to have an appointment with staff of the scientific institute. The secretariat will then send a list of proposed appointments to all the staff concerned. As soon as the secretariat has received feedback from all staff members, it will send the final appointment to each of them.
Create the corresponding UML Sequence Diagram.
My answer:
c) Implement the process from (b) in Java (method bodies are sufficient!). In doing so, adhere to the classes, abstract classes, and interfaces defined in (a).
My answer:
I tried to solve this problem, but I didn't get any further, especially that it is about solving the task with abstract classes and interfaces. I think this subtask can be solved without abstract classes and interfaces, right?
should the scientific institute be implemented as an abstract class?
Can someone please explain it to me? Thanks so much :)

