Spring Boot interview questions

Model how /actuator/health combines multiple health indicators into one overall status. Implement entryPoint(Map<String, String> componentStatuses). Each entry maps a component name to its own status: "UP", "DOWN",

Model a metric tag cardinality guard. Implement entryPoint(List<Map<String, String>> events, int limit). Each entry in events is the set of tags recorded with one metric observation (e.g. {"status": "200", "userId": "u1"}). For every

What does adding spring-boot-starter-actuator give you out of the box, and why are most of its endpoints not exposed over HTTP by default?

You need a custom health check — say, verifying a downstream payment API is reachable — surfaced through /actuator/health. How do you add it, and how does Spring Boot combine multiple health indicators into the one overall status the endpoint reports?

Model a simplified @ConditionalOnClass. Implement entryPoint(Set<String> classpath, List<List<String>> candidates). Each entry in candidates is a two-element list [beanName, requiredClassName], representing an auto-configuration that would

Model @ConditionalOnMissingBean precedence. Implement entryPoint(List<String> userDefinedBeans, List<String> autoConfigCandidateBeanNames). userDefinedBeans are beans the user's own @Configuration already registered (always kept, in the given order). Then walk