Interview kitsBlog

Your dream job? Lets Git IT.
Interactive technical interview preparation platform designed for modern developers.

XGitHub

Platform

  • Categories

Resources

  • Blog
  • About the app
  • FAQ
  • Feedback

Legal

  • Privacy Policy
  • Terms of Service

© 2026 LetsGit.IT. All rights reserved.

LetsGit.IT/Categories/Spring
Springmedium

@Component vs @Bean?

Tags
#annotation#configuration#bean#spring
Back to categoryPractice quiz

Answer

@Component marks a class for component scanning so Spring registers it automatically as a bean. @Bean is used on a method inside a @Configuration class to register the returned object as a bean, often for third‑party types or custom instantiation. Both become managed beans.

Advanced answer

Deep dive

Expanding on the short answer — what usually matters in practice:

  • Context (tags): annotation, configuration, bean, spring
  • Lifecycle: what happens at runtime (render/build, request/response, background jobs).
  • Caching: where cache lives, cache keys, how to invalidate without chaos.
  • Security: authn/authz, secrets, attack surface (SSRF/CSRF).
  • Explain the "why", not just the "what" (intuition + consequences).
  • Trade-offs: what you gain/lose (time, memory, complexity, risk).
  • Edge cases: empty inputs, large inputs, invalid inputs, concurrency.

Examples

A tiny example (an explanation template):

// Example: discuss trade-offs for "@component-vs-@bean?"
function explain() {
  // Start from the core idea:
  // @Component is for auto-scanning classes. @Bean is used in @Configuration classes to explic
}

Common pitfalls

  • Too generic: no concrete trade-offs or examples.
  • Mixing average-case and worst-case (e.g., complexity).
  • Ignoring constraints: memory, concurrency, network/disk costs.

Interview follow-ups

  • When would you choose an alternative and why?
  • What production issues show up and how do you diagnose them?
  • How would you test edge cases?

Related questions

Spring
BeanFactory vs ApplicationContext: what’s the practical difference?
#spring#ioc#applicationcontext
Spring
WebClient vs RestTemplate: which should you use and why?
#spring#webclient#resttemplate
Spring
`@Scheduled`: fixedRate vs fixedDelay vs cron — what’s the difference?
#spring#scheduling#cron
Spring
`@Async` methods: how do they work and what are common pitfalls?
#spring#async#executor
Spring
Bean lifecycle callbacks: what do `@PostConstruct` and `@PreDestroy` do?
#spring#lifecycle#postconstruct
Spring
`@RestController` vs `@Controller`: what’s the difference?
#spring#mvc#controller