Create a Class UML diagram for the Blackboard system

Create a Class UML diagram for the Blackboard system. Assume that object-oriented techniques will be used. Include at least one attribute and one method for each object. Include at least one inherited relationship. Include at least 5 classes.

The correct answer and explanation is :

Here is the UML class diagram for the Blackboard system. It includes the following classes:

1. User: This class represents general users of the system. It contains attributes such as userId and userName. The method login() is included to allow users to log into the system.
2. Instructor (inherits from User): Instructors are users who teach courses. They inherit attributes and methods from the User class, but also have unique methods like postGrade() and attributes like instructorId.
3. Student (inherits from User): Students are users who take courses. They inherit attributes and methods from User but also have the method submitAssignment() and an attribute studentId.
4. Course: This class represents the courses in the system. It contains attributes like courseName and courseCode. The method addAssignment() is used to add new assignments to a course.
5. Assignment: This class represents an assignment for a course. It contains attributes like assignmentTitle and dueDate, with methods like gradeAssignment() to grade assignments.

The inheritance relationship between Instructor and User means that instructors are a specialized type of user, inheriting common attributes and behaviors like userId and login(). The system ensures that both students and instructors can access common features (such as logging in) but also provides additional functionalities based on their roles.

This structure supports object-oriented design principles, promoting reuse and organization within the system.