Back-End Development Development 2 — Questions and Answers
Question 1: Which HTTP status code should an API return when a requested resource is not found?
- 200 OK
- 301 Moved Permanently
- 404 Not Found (Correct answer)
- 500 Internal Server Error
Correct answer: 404 Not Found
404 Not Found indicates the server could not locate the requested resource.
Question 2: In RESTful API design, which HTTP method is idempotent AND safe?
- POST
- PUT
- DELETE
- GET (Correct answer)
Correct answer: GET
GET is both idempotent (multiple identical requests produce the same result) and safe (it does not modify server state).
Question 3: What does the CAP theorem state about distributed systems?
- Consistency, Availability, and Partition tolerance cannot all be guaranteed simultaneously (Correct answer)
- Caching, Authentication, and Performance must be balanced
- Every database must choose between SQL and NoSQL
- CPU, API calls, and Persistence are the three pillars of scaling
Correct answer: Consistency, Availability, and Partition tolerance cannot all be guaranteed simultaneously
CAP theorem states a distributed system can guarantee at most two of the three properties: Consistency, Availability, and Partition tolerance.
Question 4: Which pattern separates the construction of a complex object from its representation?
- Singleton
- Observer
- Builder (Correct answer)
- Facade
Correct answer: Builder
The Builder pattern allows step-by-step construction of complex objects while keeping the construction process independent of the final representation.
Question 5: What is the primary purpose of database connection pooling in back-end applications?
- To encrypt database credentials
- To reuse existing database connections and reduce overhead (Correct answer)
- To automatically back up the database
- To distribute queries across multiple databases
Correct answer: To reuse existing database connections and reduce overhead
Connection pooling maintains a cache of reusable database connections, reducing the cost of repeatedly opening and closing connections.
Question 6: Which of the following best describes a microservices architecture?
- A single deployable unit containing all application logic
- An application built as a collection of small, independently deployable services (Correct answer)
- A pattern where all services share a single database
- A framework for building mobile back-ends
Correct answer: An application built as a collection of small, independently deployable services
Microservices decompose an application into small, independently deployable services that communicate over a network.
Question 7: What is the role of an API gateway in a microservices system?
- To store all service data in one place
- To act as a single entry point that routes requests to appropriate services (Correct answer)
- To compile microservices into a single binary
- To replace the need for load balancers
Correct answer: To act as a single entry point that routes requests to appropriate services
An API gateway serves as the single entry point for clients, handling routing, authentication, rate limiting, and aggregation across services.
Back-End Development Development 2
Which HTTP status code should an API return when a requested resource is not found?