Enums.java

enum Products {
  BF(4.0),L(6.0);
}

enum LessonStatus {
  STARTED, CANCELLED, ETC;
}

enum Subject {
  Accounting(LocalTime.of(12, 0)),..
}

enum Notes implements Subject {
  
}

interface Cafeteria {
  private Map<Person, List<Products>> sales;
  void buyItem(Person customer, Products product);
  
}

Lesson(Teacher teacher, LocalTime time, Subject subject, String title) {}