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System Design

System design interviews test your ability to trade off between correctness, performance, scalability, and maintainability at the architecture level. For senior Java/Spring Boot engineers, this means understanding microservices trade-offs, database selection, caching strategies, API design, and reliability patterns (circuit breaker, retry, bulkhead, rate limiting).

What You'll Find Here

Notes are being added. Planned topics:

TopicDescription
SOLID PrinciplesSingle Responsibility, Open/Closed, Liskov, Interface Segregation, Dependency Inversion.
MicroservicesService decomposition, inter-service communication (REST vs. messaging), eventual consistency.
API DesignREST vs. gRPC vs. GraphQL; versioning; pagination; rate limiting.
Caching StrategiesCache-aside, write-through, write-behind; eviction policies; cache stampede.
Reliability PatternsCircuit Breaker (Resilience4j), Retry, Bulkhead, Timeout, Rate Limiter.
Distributed SystemsCAP theorem, consistency models, idempotency, distributed transactions (Saga pattern).
Scalability PatternsHorizontal vs. vertical scaling, stateless services, read replicas, sharding.

Learning Path

  1. SOLID Principles — these are the “grammar” of good OOP design; expected at every level.
  2. Caching Strategies — cache-aside with Redis is the most common pattern; understand eviction and consistency trade-offs.
  3. Reliability Patterns — Circuit Breaker and Retry with Resilience4j appear in almost every microservices setup.
  4. Microservices — service decomposition trade-offs and inter-service communication choices are standard interview questions.
  5. Distributed Systems — CAP theorem, eventual consistency, and Saga are senior-level topics.
  • Spring Boot — most distributed system patterns have Spring Boot implementation examples.
  • Messaging — Saga and event-driven architectures rely on Kafka or RabbitMQ.
  • Databases — database selection, sharding, and replication are system design concerns.