Start by clarifying requirements and constraints, then outline a design using a thread-safe queue and lazy initialization with double-checked locking. Implement the core operations (acquire, release, close) with proper synchronization and timeout handling, and discuss trade-offs and edge cases.
Pro tip: Demonstrate awareness of real-world concurrency pitfalls like deadlocks and resource leaks by explicitly discussing how your design prevents them, and mention testing with stress tests and race detectors.
Ask questions to confirm expected behavior: maximum pool size, timeout semantics, whether connections are created eagerly or lazily, and how close should behave for both pool and connections.
Choose a thread-safe collection (e.g., BlockingQueue) for idle connections, use atomic variables or locks for state, and plan lazy initialization with double-checked locking or a holder class.
Code acquire() to block with timeout when pool is exhausted, release() to return connections, and close() to shut down the pool safely, ensuring no new acquisitions and proper cleanup.
Address scenarios like timeout during acquisition, closing while connections are in use, double close, and ensure no resource leaks or deadlocks.
Explain choices (e.g., fairness, timeout precision) and how you would test concurrency (stress tests, race detectors) and verify correctness.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.