In Spring Boot, which annotation is used to define a class as a global advice for all controllers?
- @Controller
- @RestController
- @ControllerAdvice
- @GlobalAdvice
In Spring Boot, the @ControllerAdvice annotation is used to define a class as global advice for all controllers. This class can contain methods annotated with @ExceptionHandler, @InitBinder, or @ModelAttribute, which are applied globally to controllers. It's a crucial mechanism for adding cross-cutting concerns, such as exception handling, to your Spring Boot application. The other options are not used for this purpose.
Which annotation is used to denote a test method in JUnit?
- @JUnit
- @Run
- @Test
- @Unit
In JUnit, the @Test annotation is used to denote a test method. It marks a method as a test case that should be run by the JUnit test runner.
You are building a microservices architecture using Spring Cloud. How would you manage external configurations and secrets across different microservices?
- Storing configurations and secrets directly in the codebase.
- Using a centralized configuration server like Spring Cloud Config Server.
- Distributing configuration files via email to team members.
- Hardcoding configurations in each microservice.
In a microservices architecture, managing configurations and secrets centrally is essential. Spring Cloud provides Spring Cloud Config Server, which allows you to store configurations in a centralized location. Options 1, 3, and 4 are not recommended practices and can lead to maintenance challenges.
Imagine you are working on a large Spring Boot application with numerous controllers, and you need to ensure consistent handling of validation errors across all controllers. How would you approach this?
- Define custom error pages for validation errors in the application's HTML or Thymeleaf templates. Configure the controllers to redirect to these error pages when validation errors occur, ensuring a consistent user experience.
- Implement a global exception handler by creating a custom exception handler class annotated with @ControllerAdvice and define methods to handle validation-related exceptions. Configure the application to use this global exception handler to ensure consistent handling of validation errors across all controllers.
- Manually handle validation errors in each controller method by using try-catch blocks and returning appropriate error responses. Maintain consistency by following a standardized error response structure in each controller method.
- Use Spring Boot's built-in global validation error handling, which automatically handles validation errors and returns standardized error responses without the need for explicit exception handling in controllers. Customize the error messages and response format as needed in the application properties.
To ensure consistent handling of validation errors across all controllers in a Spring Boot application, you should implement a global exception handler using @ControllerAdvice. This allows you to define methods to handle validation-related exceptions consistently across the application.
How can you handle cache eviction in a distributed caching environment in Spring Boot?
- Use a time-based eviction policy in the cache configuration.
- Implement cache eviction listeners for real-time updates.
- Manually remove cached items based on usage patterns.
- Configure cache eviction through a scheduled task.
Handling cache eviction in a distributed caching environment in Spring Boot often involves implementing cache eviction listeners. These listeners can react to changes in the underlying data source and ensure that the cache stays up-to-date. Option 1 suggests a time-based eviction policy, which is one way to handle eviction but might not be suitable for all scenarios. Options 3 and 4 describe manual approaches to cache eviction, which are less common in distributed caching setups.
You are tasked with securing a large-scale Spring Boot application with various microservices. How would you design the security architecture to ensure that the services are securely accessible and user authentication and authorization are handled efficiently?
- Implementing security separately for each microservice
- Using OAuth2 with JWT tokens for authentication and authorization
- Storing user credentials in plaintext in a centralized database
- Using HTTP Basic Authentication for all services
To secure a large-scale Spring Boot application with microservices efficiently, it's advisable to use OAuth2 with JWT tokens. This approach provides centralized authentication and authorization while allowing secure access to services. The other options have security and efficiency drawbacks, such as storing credentials in plaintext or using HTTP Basic Authentication, which are not recommended for production scenarios.
How can you handle different HTTP methods in a single method in a Spring Boot controller?
- Create separate controller classes for each HTTP method.
- Use multiple methods with different names for each HTTP method.
- Use the @RequestMapping annotation with the method parameter.
- Use the @RequestMethod annotation with the method parameter.
To handle different HTTP methods in a single method of a Spring Boot controller, you can use the @RequestMapping annotation with the method parameter. This allows you to specify which HTTP methods (GET, POST, PUT, DELETE, etc.) should be mapped to that method. Inside the method, you can use conditional logic to perform different actions based on the incoming HTTP method.
For optimizing database connection pooling in Spring Boot, adjusting the _____ property is crucial.
- spring.application.name
- spring.datasource.maxIdle
- spring.jpa.hibernate.ddl-auto
- spring.mvc.view.prefix
For optimizing database connection pooling in Spring Boot, adjusting the spring.datasource.maxIdle property is crucial. This property configures the maximum number of idle database connections in the pool, which can significantly impact the application's performance and resource utilization. By tuning this property, you can ensure efficient database connection management.
What are the security considerations when validating a JWT token in a Spring Boot application?
- Ensure the JWT token is signed using a strong algorithm and verify the signature.
- Expose the JWT token in URL parameters for ease of access.
- Trust all JWT tokens originating from the same issuer.
- Validate the JWT token only on the client side.
When validating a JWT token in a Spring Boot application, you must ensure that the token is signed using a strong algorithm and verify the signature to ensure its authenticity. Trusting all JWT tokens from the same issuer or exposing tokens in URL parameters are security risks. Validating the JWT token only on the client side is insufficient as it lacks server-side validation.
You are tasked with implementing API Gateway in a Spring Cloud microservices environment. What considerations and configurations would you take into account to ensure proper routing, filtering, and security?
- Routing based on hardcoded paths.
- Implementing authentication and authorization filters.
- Using the same API Gateway for all microservices.
- No security measures.
Proper API Gateway implementation requires considerations for routing, filtering, and security. Implementing authentication and authorization filters is crucial for security. Hardcoded routing and ignoring security measures are not recommended practices.