In Spring Boot, _____ is used to enable caching capability in the application.
- @CacheConfig
- @Cacheable
- @EnableCaching
- @Caching
In Spring Boot, the @EnableCaching annotation is used to enable caching capability in the application. It allows you to use caching annotations like @Cacheable and @CacheEvict to control caching behavior. The other options are related to caching but not used for enabling caching at the application level.
How can you resolve circular dependencies between beans in Spring Boot?
- Using @Lazy annotation to delay bean initialization.
- Ensuring that all beans depend on each other.
- Setting the application context to auto-detect-circular-dependencies: true.
- Using the @DependsOn annotation to specify bean dependencies explicitly.
Circular dependencies can be resolved in Spring Boot by using the @Lazy annotation to delay the initialization of beans involved in the circular dependency. This allows Spring to break the circular reference. The other options do not effectively resolve circular dependencies and may lead to issues.
In Spring Boot, which annotation is typically used to enable caching in an application?
- @EnableCaching
- @CacheControl
- @Cacheable
- @Caching
In Spring Boot, the @EnableCaching annotation is typically used to enable caching in an application. It allows you to activate the caching functionality for your Spring Boot application. The other options are not used for enabling caching but rather for specifying caching behavior or configuring cache entries.
In a Spring Boot application, how can you validate a field based on multiple conditions or constraints?
- Using only the @NotNull annotation
- Combining multiple annotations like @Min, @Max, and @Pattern
- Creating a custom validator class for each condition
- Using JavaScript to validate the field on the client-side
To validate a field based on multiple conditions or constraints in a Spring Boot application, you can combine multiple annotations like @Min, @Max, and @Pattern. These annotations allow you to define various rules for a single field. Creating a custom validator class for each condition (Option 3) would be cumbersome and is not the recommended approach.
Which grant type would be most suitable for a mobile application that needs to access services on behalf of the user?
- Authorization Code Grant
- Client Credentials Grant
- Implicit Grant
- Resource Owner Password Credentials Grant
For a mobile application that needs to access services on behalf of the user, the Authorization Code Grant is most suitable. This grant type involves a redirection-based flow where the user authenticates themselves on the authorization server, and the mobile app receives an authorization code, which can be securely exchanged for an access token. This is a more secure approach compared to the Implicit Grant, which is suitable for browser-based apps. The other grant types are not typically used for mobile apps accessing on behalf of the user.
Which Spring Security annotation is used to apply security constraints at the method level based on SpEL expressions?
- @PreFilter
- @PostFilter
- @PreAuthorize
- @PostAuthorize
The @PreAuthorize annotation is used to apply security constraints at the method level based on SpEL (Spring Expression Language) expressions. You can define complex conditions using SpEL to control method access. The other options are used for filtering, not method-level security.
How can you manage bean lifecycle events, such as initialization and destruction, in Spring Boot?
- By using the @Bean annotation with @PostConstruct and @PreDestroy methods.
- By declaring beans in an XML configuration file.
- By using the @Service annotation with initMethod and destroyMethod attributes.
- By configuring bean lifecycles in the main application class constructor.
You can manage bean lifecycle events, such as initialization and destruction, in Spring Boot by using the @Bean annotation along with @PostConstruct and @PreDestroy methods. These methods allow you to specify custom initialization and destruction logic for your beans. The other options mentioned (XML configuration, @Service with initMethod and destroyMethod, and configuring lifecycles in the main application class constructor) are not the recommended or common approaches for managing bean lifecycles in Spring Boot.
Imagine you are developing a Spring Boot application where you need to validate incoming request payloads against a complex business rule. How would you approach implementing such a validation?
- Use custom validation annotations.
- Implement validation logic in a filter or interceptor.
- Embed validation logic in the data access layer.
- Use a third-party validation library.
When dealing with complex validation rules in a Spring Boot application, one effective approach is to use custom validation annotations. This allows you to define and apply custom validation logic directly to your model classes, keeping your code clean and maintainable. While the other options may work for simpler scenarios, they are less suitable for complex business rule validation.
When dealing with multiple exception resolver beans in Spring Boot, how can you define the order of their execution?
- By configuring the 'order' property in the application.properties file.
- By setting the 'order' property in the @ExceptionHandler annotation.
- By specifying the order in which beans are defined in the application context.
- By using the @Order annotation on the exception resolver bean classes.
When dealing with multiple exception resolver beans in Spring Boot, you can define the order of their execution by using the @Order annotation on the exception resolver bean classes. This annotation allows you to specify the order in which the beans should be prioritized. Beans with lower order values are executed before those with higher order values. This approach gives you fine-grained control over the execution order of exception resolvers.
How do you access the data sent in the request body of a POST request in a Spring Boot controller method?
- Using the @RequestParam annotation.
- By retrieving it from the HttpServletRequest object.
- By declaring a method parameter annotated with @RequestBody.
- It is automatically available as a method argument.
To access the data sent in the request body of a POST request in a Spring Boot controller method, you should declare a method parameter and annotate it with @RequestBody. This annotation tells Spring to deserialize the request body data into the specified object or data type. The other options, such as @RequestParam and retrieving it from HttpServletRequest, are used for different scenarios and do not directly handle the request body of a POST request.