Spring Cloud

Spring Cloud as an integration ecosystem for distributed-service concerns, with version-train compatibility and evolving components.

Centralized configuration, namespaces, change delivery, local caching, and operational considerations for Apollo-style config systems.

Eureka-style client registration and discovery, heartbeats, cached registries, and availability-oriented semantics.

Declarative HTTP interfaces, encoding/decoding, errors, timeouts, retries, and service-discovery integration.

Reactive API gateway routing, filters, cross-cutting policy, and the importance of non-blocking/backpressure-safe customization.

Historical Hystrix circuit breaker, timeout, fallback, and isolation concepts that remain useful even though the library is legacy.

Historical Ribbon client-side load balancing and durable instance-selection concepts.

Distributed trace/span propagation concepts and the transition from Spring Cloud Sleuth to newer observability stacks.

Netflix Zuul gateway/filter architecture and its place as historical context beside newer Spring gateway stacks.

Thread/semaphore bulkhead isolation, bounded queues, timeout behavior, and modern resilience interpretation.