Design notation drill

Draw (or describe precisely) the class diagram for a library: books with multiple physical copies, members who borrow copies, loans with due dates, reservations queued on a book, and fines. Give every relationship type and multiplicity and justify the ones an interviewer is likely to question.

Write the sequence for 'customer checks out a cart' in an e-commerce service: validating stock, reserving inventory, charging payment, creating the order and sending a confirmation. Include the failure paths, the transaction boundary, and where you would use asynchronous messages.

Design the state machine for a ride in a ride-hailing app from request to completion, including cancellations by rider and driver, no-shows and payment. List states, events, guards and actions, and explain how you prevent two drivers from accepting the same ride.

Apply the requirements-to-objects method to 'design a meeting room booking system for an office': clarify, mine nouns and verbs, classify, assign responsibilities, walk the 'book a room' flow, and then absorb the change 'recurring weekly meetings'.