Hi Guys, Welcome to JAVA INSPIRES. In this post we will see top 5p0 spring boot interview question for senior devlopers.
1. What is Spring Boot?
Spring Boot is a framework that simplifies the development of Java applications by providing opinionated defaults and automatic configuration.
2. What are the advantages of using Spring Boot?
Some advantages of using Spring Boot are:
- Simplified configuration and setup
- Embedded server support
- Automatic dependency management
- Easy integration with other Spring projects
- Production-ready features like metrics, health checks, and monitoring
3. Explain the annotations used in Spring Boot.
- `@SpringBootApplication`: This annotation is used to indicate the main class of a Spring Boot application.
- `@RestController`: It combines `@Controller` and `@ResponseBody` annotations, making it convenient for creating RESTful web services.
- `@Autowired`: It is used for automatic dependency injection.
- `@Component`: It is a generic stereotype annotation for any Spring-managed component.
4. How does Spring Boot simplify the configuration of Spring applications?
Spring Boot uses convention over configuration. It provides sensible defaults and automatically configures various components based on classpath and environment settings. This reduces the amount of configuration required, making development faster and simpler.
5. Explain the difference between Spring and Spring Boot.
Spring is a framework that provides various modules for building enterprise Java applications. Spring Boot is an opinionated framework built on top of Spring, which provides a set of defaults and conventions to simplify the development process.
6. How can you configure logging in a Spring Boot application?
Spring Boot uses the Logback framework as the default logging implementation. You can configure logging in the `application.properties` or `application.yml` file. For example, setting `logging.level.root=INFO` in `application.properties` will set the root logging level to INFO.
7. What is the purpose of the `@SpringBootTest` annotation?
The `@SpringBootTest` annotation is used to bootstrap the Spring Boot application context for integration tests. It loads the complete application context and provides various testing features.
8. How can you externalize configuration in Spring Boot?
Spring Boot allows you to externalize configuration using properties files, YAML files, environment variables, or command-line arguments. Properties can be defined in `application.properties` or `application.yml` files, and you can override them using other sources.
9. What is Spring Data JPA in Spring Boot?
Spring Data JPA is a part of the Spring Data project that provides an abstraction layer over data access frameworks like JPA (Java Persistence API). It simplifies the implementation of JPA-based repositories by providing common CRUD operations and query methods.
10. How does Spring Boot handle database transactions?
Spring Boot uses the `@Transactional` annotation to handle database transactions. When a method is annotated with `@Transactional`, Spring Boot manages the transactional boundaries and commits or rolls back the transaction based on the success or failure of the method.
11. What is the purpose of the `@RestControllerAdvice` annotation?
The `@RestControllerAdvice` annotation is used to define global exception handlers for RESTful web services. It allows you to handle exceptions in a centralized way and return consistent error responses.
12. Explain the Spring Boot Actuator.
Spring Boot Actuator provides production-ready features to monitor and manage your application. It includes endpoints for health checks, metrics, logging, thread dumps, and more. Actuator endpoints provide insights into the internals of your application.
13. What is the purpose of the `@Conditional` annotation in Spring Boot?
The `@Conditional` annotation is used to conditionally enable or disable a configuration or bean based on certain conditions. It allows you to define custom conditions using conditional annotations like `@ConditionalOnProperty`, `@ConditionalOnClass`, `@ConditionalOnBean`, etc
14. How can you secure a Spring Boot application?
You can secure a Spring Boot application using Spring Security. Spring Security provides authentication and authorization features to secure your application endpoints. You can configure security rules and use various authentication mechanisms like Basic Authentication, OAuth, etc.
15. How does Spring Boot handle externalized configuration secrets like passwords and API keys?
Spring Boot provides support for externalized secret management using tools like Vault, Kubernetes Secrets, or environment variables. You can store sensitive information outside the application code and access them securely at runtime.
16. What is the purpose of the `@Cacheable` annotation in Spring Boot?
The `@Cacheable` annotation is used to enable caching for methods. It allows you to cache the results of a method based on its arguments, improving performance by avoiding expensive computations.
17. How does Spring Boot handle internationalization (i18n)?
Spring Boot supports internationalization by providing a mechanism to resolve messages from resource bundles. You can define message properties files for different locales and use the `MessageSource` bean to retrieve the localized messages.
18. What is Spring Boot Actuator's `/health` endpoint used for?
The `/health` endpoint provided by Spring Boot Actuator is used to check the health status of your application. It can be used by monitoring systems to determine if the application is running properly.
19. Explain the role of Spring Boot Starter POMs.
Spring Boot Starter POMs are a set of dependency descriptors that simplify dependency management. They provide a convenient way to add dependencies for common use cases, such as web applications (`spring-boot-starter-web`), data access with JPA (`spring-boot-starter-data-jpa`), etc.
20. How can you enable cross-origin resource sharing (CORS) in a Spring Boot application?
You can enable CORS in a Spring Boot application by adding the `@CrossOrigin` annotation to your controller methods or by configuring global CORS settings using `WebMvcConfigurer`.
21. How does Spring Boot support messaging with Apache Kafka?
Spring Boot provides the Spring Kafka project, which offers abstractions and integration with Apache Kafka. It allows you to produce and consume messages from Kafka topics using the `KafkaTemplate` and `@KafkaListener` annotations.
22. What is the purpose of the `@ConfigurationProperties` annotation in Spring Boot?
The `@ConfigurationProperties` annotation is used to bind externalized configuration properties to a Java bean. It allows you to map configuration properties to fields or setter methods of a class, simplifying the process of reading configuration values.
23. How does Spring Boot support asynchronous programming?
Spring Boot provides support for asynchronous programming using the `@Async` annotation and the `CompletableFuture` class. By annotating a method with `@Async`, you can execute it asynchronously, and the result can be obtained using a `CompletableFuture` object.
24. What is the purpose of the `@Scheduled` annotation in Spring Boot?
The `@Scheduled` annotation is used to schedule the execution of a method at fixed intervals or according to a cron expression. It allows you to automate repetitive tasks in your application.
25. How can you handle form validation in Spring Boot?
Spring Boot integrates with Hibernate Validator to provide form validation support. You can annotate your form objects with validation constraints, and Spring Boot will automatically validate the form data based on the annotations.
26. What is the purpose of the Spring Boot DevTools?
Spring Boot DevTools is a set of tools that provide developer productivity enhancements. It includes features like automatic application restart on code changes, browser live reloading, remote debugging, and more.
27. How can you enable HTTP/2 support in a Spring Boot application?
To enable HTTP/2 support in a Spring Boot application, you need to include an appropriate server dependency (e.g.,
Tomcat 9) and configure it to use the HTTP/2 protocol. Additionally, you may need to configure SSL/TLS for secure communication.
28. How does Spring Boot support GraphQL?
Spring Boot integrates with libraries like GraphQL Java and GraphQL Spring Boot to provide support for building GraphQL APIs. You can define GraphQL schemas, resolvers, and queries using annotations and leverage Spring Boot features for easy integration.
29. What is the purpose of the `@EntityScan` annotation in Spring Boot?
The `@EntityScan` annotation is used to specify the base packages to scan for JPA entities. It is typically used when the entities are not located in the same package or a subpackage of the main application class.
30. How can you implement distributed caching in a Spring Boot application?
Spring Boot provides integration with distributed caching systems like Redis or Hazelcast. By adding the appropriate dependencies and configuring the cache manager, you can use distributed caches to improve the performance of your application.
31. What is the role of Spring Boot Actuator's `/info` endpoint?
The `/info` endpoint provided by Spring Boot Actuator allows you to provide custom application information. It can be used to expose additional details about the application, such as version number, build information, environment details, etc.
32. How does Spring Boot support reactive programming?
Spring Boot integrates with Spring WebFlux to provide support for reactive programming. It allows you to build non-blocking, event-driven applications using reactive streams and provides integration with reactive web frameworks like Netty and Undertow.
33. What is the purpose of the `@RequestMapping` annotation in Spring Boot?
The `@RequestMapping` annotation is used to map a URL pattern or HTTP method to a controller method. It defines the endpoint that will handle the incoming requests and perform the necessary processing.
34. How can you customize the JSON serialization and deserialization in a Spring Boot application?
Spring Boot uses Jackson as the default JSON library. You can customize the serialization and deserialization by creating a custom `JsonSerializer` or `JsonDeserializer` and configuring it using `@JsonSerialize` or `@JsonDeserialize` annotations.
35. What is the purpose of the `@Retryable` annotation in Spring Boot?
The `@Retryable` annotation is used to enable automatic retry of a method in case of a specified exception. It allows you to configure the number of retries, backoff strategy, and other parameters to control the retry behavior.
36. How can you configure multiple data sources in a Spring Boot application?
Spring Boot provides support for multiple data sources by configuring multiple `DataSource` beans with different configurations. You can use the `@Primary` annotation to specify the primary data source, and `@Qualifier` to differentiate between multiple data sources.
37. What is the purpose of the `@EnableCaching` annotation in Spring Boot?
The `@EnableCaching` annotation is used to enable Spring's caching support in a Spring Boot application. It activates the caching infrastructure and allows you to use annotations like `@Cacheable` and `@CacheEvict` for caching method results.
38. How does Spring Boot handle versioning of RESTful APIs?
Spring Boot provides several strategies for versioning RESTful APIs, including URL-based versioning, request parameter-based versioning, and header-based versioning. You can choose the strategy that best suits your application's requirements.
39. What is the purpose of the `@EnableScheduling` annotation in Spring Boot?
The `@EnableScheduling` annotation is used to enable scheduled task execution in a Spring Boot application. It activates the scheduling infrastructure and allows you to use the `@Scheduled` annotation to schedule method invocations.
40. How can you implement distributed tracing in a Spring Boot application?
Spring Boot integrates with distributed tracing systems like Zipkin or Jaeger. By adding the appropriate dependencies and configuring the tracing settings, you can trace requests across different services and gain insights into the application's performance.
41. What is the purpose of the `@ControllerAdvice` annotation in Spring Boot?
The `@ControllerAdvice` annotation is used to define global exception handlers for MVC controllers. It allows you to handle exceptions in a centralized way and customize the error responses for your application.
42. How can you handle file uploads in a Spring Boot application?
Spring Boot provides support for file uploads through the use of the `@RequestParam` annotation and the `MultipartFile` class. You can create an endpoint that accepts file uploads and process them accordingly.
43. What is the purpose of the `@Transactional` annotation in Spring Boot?
The `@Transactional` annotation is used to define a method or class as transactional. It ensures that the method's execution is wrapped within a transaction, allowing for ACID (Atomicity, Consistency, Isolation, Durability) properties in database operations.
44. How can you implement asynchronous messaging in a Spring Boot application?
Spring Boot supports asynchronous messaging through integration with messaging systems like RabbitMQ or Apache Kafka. By configuring the appropriate dependencies and using annotations like `@RabbitListener` or `@KafkaListener`, you can consume and produce messages asynchronously.
45. What is the purpose of the `@GetMapping` annotation in Spring Boot?
The `@GetMapping` annotation is a shortcut for mapping HTTP GET requests to a specific method in a controller class. It simplifies the process of defining endpoints for handling GET requests.
46. How can you handle authentication and authorization in a Spring Boot application?
Spring Boot integrates with Spring Security to provide authentication and authorization features. You can configure authentication mechanisms, define security rules, and secure your application endpoints using annotations like `@Secured` or `@PreAuthorize`.
47. What is the purpose of the `@Value` annotation in Spring Boot?
The `@Value` annotation is used to inject values from configuration properties or environment variables into a Spring bean. It allows you to easily access configuration values and use them in your application.
48. How can you implement circuit-breaking and resilience patterns in a Spring Boot application?
Spring Boot integrates with libraries like Netflix Hystrix or Resilience4j to implement circuit-breaking and resilience patterns. By configuring the appropriate dependencies and annotations, you can protect your application from cascading failures and handle failures gracefully.
49. What is the purpose of the Spring Boot Actuator's `/metrics` endpoint?
The `/metrics` endpoint provided by Spring Boot Actuator allows you to gather and expose application-specific metrics. It provides insights into the application's performance, resource usage, and other metrics that can be used for monitoring and analysis.
50. How can you customize the error handling and exception responses in a Spring Boot application?
Spring Boot allows you to customize error handling and exception responses by implementing custom exception handlers using `@ControllerAdvice` or by extending the `ResponseEntityExceptionHandler` class. You can define how different types of exceptions are handled and return appropriate error responses.
These questions cover a range of topics related to Spring Boot and are commonly asked in interviews for senior developers and architects. It's important to understand the concepts behind these questions and be able to explain them clearly during an interview.
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spring boot