Spring Cloud Cheat Sheet 2026

The 30 highest-yield Spring Cloud facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which metric dimension should a Spring Cloud architect monitor to assess the health of a circuit breaker in production? → Circuit breaker state (CLOSED, OPEN, HALF_OPEN), call volume, and failure rate
2. How should Spring Cloud professionals apply research findings to practice? → Critically evaluate applicability, adapt to context, and monitor outcomes
3. Which Spring Cloud component provides a pattern for preventing cascading failures across microservices? → Spring Cloud Circuit Breaker
4. What annotation enables a Spring Boot application to act as a Eureka Discovery Server? → @EnableEurekaServer
5. How does continuous improvement apply to Spring Cloud quality management? → It involves ongoing incremental enhancements to processes based on data and feedback
6. What exactly is spring? → Spring is an open source development framework for enterprise Java.
7. What are the three states a circuit breaker cycles through in the circuit breaker pattern? → Closed, Open, Half-Open
8. Which Spring Cloud Vault feature directly supports PCI-DSS Requirement 3 (protect stored cardholder data)? → Transit secrets engine for encrypting cardholder data at rest
9. Which Spring Security feature is most directly relevant to HIPAA's requirement for unique user identification in a Spring Cloud app? → UserDetailsService with unique principal assignment
10. Which Spring Cloud Gateway feature allows defining routes programmatically in Java instead of YAML configuration? → Fluent Java DSL using RouteLocatorBuilder
11. What exactly is an aspect? → A module which has a set of APIs providing cross-cutting requirements
12. How do Spring Cloud professionals evaluate research quality? → By assessing methodology, sample size, peer review status, and relevance to practice
13. A Spring Cloud microservice relies on Eureka for discovery but has no client-side retry configured. What failure scenario does this leave unaddressed? → Requests hitting a just-deregistered but still-cached stale Eureka entry
14. Which actuator endpoint must be exposed to trigger a live configuration refresh on a Spring Cloud Config client without restarting? → /actuator/refresh
15. A Spring Cloud Gateway is used as an API gateway. Which filter type is best for implementing PCI-DSS requirement of masking PANs in logs? → GatewayFilter that sanitizes request/response logging
16. Which Spring Cloud component would you recommend to a stakeholder who needs asynchronous, broadcast configuration refresh across all microservice instances? → Spring Cloud Bus
17. Which Spring Cloud project provides service discovery support using HashiCorp Consul? → Spring Cloud Consul
18. In Spring, what are the IoC containers? → BeanFactory, ApplicationContext
19. In Spring Cloud Gateway, which built-in filter adds a request rate limiting capability to protect downstream services? → RequestRateLimiter GatewayFilter
20. How has digital technology transformed Spring Cloud practice? → It has enhanced data collection, analysis, communication, and operational efficiency
21. For HIPAA Security Rule compliance, Spring Cloud service-to-service communication must use encryption in transit. What is the recommended approach? → Mutual TLS (mTLS) between services using Spring Cloud certificate management
22. Which Resilience4j metric should you monitor to detect slow degradation risk before the circuit breaker opens? → resilience4j.circuitbreaker.slow.call.rate
23. A financial firm needs all inter-service HTTP calls logged with a shared trace ID for audit purposes. Which Spring Cloud component provides this out of the box? → Spring Cloud Sleuth (Micrometer Tracing)
24. Which Spring Cloud Config Server backend stores configuration in a relational database rather than Git? → JDBC backend (spring.cloud.config.server.jdbc)
25. What does the `@LoadBalanced` annotation do when applied to a RestTemplate bean in Spring Cloud? → Intercepts requests to resolve logical service names via the discovery client
26. After enabling Spring Cloud Sleuth, a team finds trace IDs are not propagating through Kafka messages between services. What must they add? → Spring Cloud Sleuth Kafka binder instrumentation or Micrometer Tracing Kafka propagation
27. What is the importance of data security in Spring Cloud digital applications? → Protecting sensitive information from unauthorized access, breaches, and loss is essential
28. When using Resilience4j Retry with Spring Cloud, what risk does setting maxAttempts too high introduce for non-idempotent operations? → Duplicate side effects such as multiple payments or order submissions
29. Which of the following statements regarding dependency injection is correct? → It helps in decoupling application objects from each other.
30. Which Spring Cloud Config feature reduces the risk of secrets being exposed in plaintext in a Git repository? → Symmetric or asymmetric property encryption