Design a Library Management System Object-Oriented Design Interview
Design a library that models catalog titles versus physical copies, members and librarians, checkout/return/renew/reserve flows with loan due dates, an overdue fine policy, and notifications as a boundary.
1. Problem Statement
Design a library management system: members check out, return, and renew physical copies of catalogued titles, and can place a hold on a title with no available copy. Loans have due dates, late returns incur a fine, and members are notified when a hold becomes available. Start by clarifying scope and the key objects.
2. Live Coding Format
Work in the provided coding workspace while explaining your decisions to the live interviewer. Validation may use inline tests, examples, comments, or a verbal walkthrough.
3. Key Focus Areas
- 1Title vs. physical Copy modeling
- 2Checkout / return / renew / reserve lifecycle
- 3Reservation (hold) queue ordering and renewal blocking
- 4FinePolicy strategy and NotificationService boundary
4. What Strong Candidates Should Demonstrate
- ✓Separate a catalog Title from its physical Copies and give each clear ownership.
- ✓Model loans, due dates, and an ordered reservation queue with correct invariants.
- ✓Encapsulate copy-status transitions so contradictory states are impossible.
- ✓Isolate fine calculation behind a policy and notifications behind a boundary.
Want interactive feedback?
Practice this problem in the live coding workspace while the interviewer probes your clarification, implementation, trade-offs, and validation.
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