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🔥 Top 30 Spring Boot Interview Questions (2025 Edition)

 

🔥 Top 30 Spring Boot Interview Questions (2025 Edition)

If you’re preparing for a backend developer interview, chances are high you’ll face questions on Spring Boot. It’s one of the most widely used frameworks for building scalable, production-ready applications.

In this blog, I’ve compiled the Top 30 Spring Boot Interview Questions covering basic, intermediate, and advanced levels. Whether you’re a fresher or an experienced developer, this guide will help you crack your next interview.

⭐ Basic Spring Boot Interview Questions

1. What is Spring Boot, and how is it different from Spring Framework?
Spring Boot simplifies application development by reducing boilerplate configuration. Unlike Spring, it comes with auto-configuration, embedded servers, and starters.

2. What are the advantages of using Spring Boot?

  • Rapid development

  • Production-ready features (Actuator, metrics)

  • Auto-configuration

  • Embedded server support

3. What is the role of @SpringBootApplication annotation?
It is a combination of:

  • @Configuration

  • @EnableAutoConfiguration

  • @ComponentScan

4. How does Spring Boot auto-configuration work?
It checks the classpath, existing beans, and application properties to configure beans automatically.

5. What are Spring Boot starters, and why are they useful?
Pre-built dependency descriptors like spring-boot-starter-web help avoid manual dependency management.

6. How do you configure properties in Spring Boot?

  • application.properties

  • application.yml

7. Difference between @Component, @Service, and @Repository?
All are stereotypes, but @Service is for business logic, @Repository for DAO, and @Component is generic.

8. How does Spring Boot embed servers like Tomcat?
It packages Tomcat/Jetty as dependencies and runs them inside the JAR/WAR.

9. What is the default scope of beans in Spring Boot?
Singleton.

10. How do you run a Spring Boot application?

  • Using main() method with SpringApplication.run()

  • mvn spring-boot:run

⚡ Intermediate Spring Boot Interview Questions

11. Difference between @RestController and @Controller?
@RestController = @Controller + @ResponseBody. It directly returns JSON/XML instead of rendering views.

12. How do you connect a Spring Boot app to a database?
By configuring datasource properties in application.properties and using Spring Data JPA.

13. What is Spring Boot Actuator?
A set of endpoints to monitor and manage applications (/health, /metrics).

14. What is Spring Boot DevTools?
It enables auto-restart, live reload, and fast development cycles.

15. How do you handle exceptions in Spring Boot?

  • @ControllerAdvice

  • @ExceptionHandler

16. Difference between @RequestParam and @PathVariable?

  • @RequestParam → Query parameters (/user?id=10)

  • @PathVariable → URI path variables (/user/10)

17. How does Spring Boot handle dependency injection?
Through @Autowired, constructor injection, and bean scanning.

18. How do you enable scheduling in Spring Boot?
By adding @EnableScheduling and @Scheduled annotations.

19. What is Spring Data JPA?
An abstraction over JPA that reduces boilerplate with JpaRepository.

20. What are profiles in Spring Boot?
Profiles allow environment-specific configurations (dev, test, prod).

🚀 Advanced Spring Boot Interview Questions

21. How does Spring Boot handle security?
With Spring Security → authentication, authorization, JWT, OAuth2.

22. Synchronous vs Asynchronous communication in Spring Boot?

  • Synchronous → REST APIs (blocking)

  • Asynchronous → Messaging (Kafka, RabbitMQ)

23. How do you implement caching in Spring Boot?
Using @EnableCaching and @Cacheable.

24. How does Spring Boot support messaging?
Through Kafka, RabbitMQ integration via starters.

25. How do microservices communicate in Spring Boot?

  • REST APIs

  • Feign Client

  • gRPC

26. How to optimize performance in Spring Boot apps?

  • Connection pooling

  • Caching

  • Lazy loading

  • Actuator metrics monitoring

27. How do you monitor Spring Boot apps?

  • Spring Boot Actuator

  • Micrometer

  • ELK Stack / Prometheus / Grafana

28. What is the difference between @Transactional at class vs method level?

  • Class level → All methods transactional by default

  • Method level → Fine-grained control

29. How do you containerize a Spring Boot app?
Using Docker → create Dockerfile, build image, run container.

30. What’s new in Spring Boot 3.x?

  • Migration to Jakarta EE namespace (javax → jakarta)

  • Better native image support (GraalVM)

  • Improved observability

🎯 Final Tips for Interviews

  • Don’t just memorize answers → practice building small Spring Boot apps.

  • Be ready to discuss real-world examples from your projects.

  • Know how to explain trade-offs (e.g., REST vs messaging, JPA vs JDBC).

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