Designing Large-Scale Java Systems

[ghost]

Question:
How would you design a highly available Java system serving millions of users?

[shivrajcodez]

Multi-instance + Load Balancer → no single point of failure
Stateless services → easy horizontal scaling
Auto-scaling → Kubernetes
Caching layer → Redis (reduce load)
DB HA → replication + sharding
Async processing → queues via Apache Kafka
Circuit breaker + retries → resilience
Health checks → liveness/readiness
Multi-region deploy → failover + low latency
Observability → logs, metrics, alerts