In a Spring Boot application, you are required to develop a feature where the response body should be customized based on the client's preference. How would you implement this feature using Spring Boot annotations?

  • Use the @ResponseBody annotation on controller methods and generate custom responses based on client preference in each method.
  • Implement content negotiation with @RequestMapping annotations to handle client preferences automatically.
  • Use the @RequestParam annotation to pass the client's preference as a parameter to controller methods and customize the response accordingly.
  • Define a custom response handler class and annotate it with @RestControllerAdvice to handle client preferences for all controllers.
To implement a feature in a Spring Boot application where the response body is customized based on client preference, you should use content negotiation with @RequestMapping annotations. This allows Spring Boot to handle client preferences automatically. Option 2 is the recommended approach as it promotes clean and efficient code. The other options may require more manual coding and could be less maintainable.

In Spring Boot, which annotation is used to handle exceptions at the controller level?

  • @ExceptionHandler
  • @ControllerAdvice
  • @RestController
  • @RequestMapping
In Spring Boot, the @ExceptionHandler annotation is used to handle exceptions at the controller level. This annotation allows you to define methods within a controller that can handle specific exceptions thrown by that controller. The other options, such as @ControllerAdvice, @RestController, and @RequestMapping, have different roles and are not used for handling exceptions directly at the controller level.

In a Spring Boot test, how can you override the properties defined in the application.properties file?

  • Create a new application-test.properties file.
  • Use @TestPropertySource annotation to load custom properties.
  • Modify application.properties directly in the test code.
  • Properties cannot be overridden in Spring Boot tests.
In Spring Boot tests, you can override properties defined in application.properties by using the @TestPropertySource annotation to load custom properties. Option (1) is incorrect as it's not a standard practice. Option (3) is incorrect because modifying application.properties directly in test code is not recommended. Option (4) is incorrect; properties can be overridden.

How does Spring Boot support reactive programming in conjunction with traditional MVC patterns?

  • By automatically adapting to the reactive or traditional approach based on the project's dependencies.
  • By forcing developers to choose between reactive or traditional MVC, with no middle ground.
  • By offering separate modules for reactive and traditional MVC development.
  • By requiring developers to write complex custom adapters.
Spring Boot supports reactive programming in conjunction with traditional MVC patterns by automatically adapting to the reactive or traditional approach based on the project's dependencies. It uses conditional configuration and auto-detection of libraries to determine whether to configure the application as reactive or traditional. This allows developers to seamlessly integrate reactive and non-reactive components within the same application, providing flexibility and compatibility with both programming models.

In Spring Boot, enabling ________ can help in reducing the startup time of the application.

  • AOT Compilation
  • Aspect-Oriented Programming
  • Component Scanning
  • Lazy Initialization
In Spring Boot, enabling "Lazy Initialization" can help in reducing the startup time of the application. Lazy initialization means that beans are created and initialized only when they are first requested, rather than eagerly during application startup. This can significantly improve startup performance, especially for large applications with many beans, as it avoids unnecessary upfront bean creation.

Which of the following annotations is used to mark a class as a source of bean definitions?

  • @Configuration
  • @Entity
  • @Repository
  • @Service
The @Configuration annotation is used to mark a class as a source of bean definitions. This means that any method annotated with @Bean within a class annotated with @Configuration will define a bean in the Spring context, allowing it to be injected into other components, services, etc. This is fundamental for creating the beans that make up the application context in a Spring application.

Imagine you have a Spring Boot application with complex security configurations. How would you perform integration tests to ensure that all security constraints and access controls are working as expected?

  • Disable security during testing.
  • Use hardcoded credentials for testing.
  • Leverage Spring Security Test to simulate authenticated users and roles.
  • Perform manual security testing after development.
Option 3 is the best approach. Spring Security Test provides utilities for simulating authenticated users and roles, allowing you to test security constraints and access controls effectively.

In which scenario would you choose WebFlux over the traditional blocking architecture in Spring Boot?

  • When synchronous processing is sufficient.
  • When the application has a low volume of incoming requests.
  • When the application is not using Spring Boot.
  • When the application requires high concurrency and responsiveness.
WebFlux is a good choice when you need to handle a large number of concurrent connections with high responsiveness. It excels in scenarios where non-blocking, asynchronous processing is crucial to avoid thread blocking and efficiently utilize system resources. In contrast, the traditional blocking architecture is suitable for applications with lower concurrency and when synchronous processing is sufficient.

The _____ annotation in JUnit is used to indicate that a method should be executed after all tests in the current test class have been run.

  • @After
  • @AfterAll
  • @AfterClass
  • @BeforeClass
In JUnit, the @AfterClass annotation is used to indicate that a method should be executed after all tests in the current test class have been run. This is often used for cleanup tasks after running a suite of tests.

When using the @WebMvcTest annotation in Spring Boot, only the _____ are typically loaded into the application context.

  • configuration files
  • controllers and related components
  • entire application context
  • service and repository beans
With @WebMvcTest, only the controllers and related components are typically loaded into the application context. This is useful for testing the web layer of your application in isolation without loading the entire context.