To authorize access to method-level security in Spring Security, the _______ annotation can be used.
- @Authorize
- @PreAuthorize
- @Secure
- @Security
To authorize access to method-level security in Spring Security, the @PreAuthorize annotation can be used. This annotation allows you to specify expressions for controlling access to methods based on user roles or custom conditions. It's a powerful tool for fine-grained authorization control.
How does enabling lazy initialization affect the startup time of a Spring Boot application?
- It has no impact on startup time.
- It significantly decreases the startup time.
- It significantly increases the startup time.
- It slightly increases the startup time.
Enabling lazy initialization in a Spring Boot application slightly increases the startup time. Lazy initialization means that beans are only created when they are first requested, rather than at application startup. While this can save memory and improve startup times for large applications, there is a small performance penalty when the bean is first used, as it has to be created on-demand. Therefore, enabling lazy initialization can slightly increase the startup time due to the overhead of creating beans when they are needed.
When unit testing Spring Boot applications, how can you mock the behavior of methods in a class?
- Using Spring's @MockBean annotation
- Using the @Autowired annotation
- Using the @InjectMocks annotation
- By directly modifying the source code
In Spring Boot, you can mock the behavior of methods in a class using the @MockBean annotation from the Spring Test framework. This annotation creates a mock of the specified class or interface, allowing you to define the behavior of its methods in your test. The other options are not the standard way to mock methods in Spring Boot unit tests.
How can you handle validation errors and display them to the user in Spring Boot?
- Handle validation errors by modifying the error messages in the application.properties file.
- Use @ExceptionHandler to create a custom exception handler for validation errors.
- Use BindingResult to capture validation errors and then handle them in your controller.
- Use the @Valid annotation on controller methods to automatically display validation errors.
In Spring Boot, you can handle validation errors by using BindingResult to capture errors during form submissions and then handle these errors in your controller. This approach allows you to provide custom error messages and logic for displaying errors to the user.
For a service to register itself with Eureka, it must have the _____ annotation in its main application class.
- @EnableDiscoveryClient
- @EnableEurekaClient
- @EurekaService
- @RegisterWithEureka
For a service to register itself with Eureka, it must have the @EnableDiscoveryClient annotation in its main application class. This annotation tells Spring Boot to enable service discovery and registration with Eureka. It is essential for ensuring that your microservices can be discovered and accessed by other services in the architecture.
In JUnit, which annotation is used to execute a method before each test method in the test class?
- @BeforeClass
- @BeforeEach
- @BeforeMethod
- @BeforeTest
In JUnit, the @BeforeEach annotation is used to execute a method before each test method in the test class. This is often used for setup operations required before each test case.
To optimize the performance of a Spring Boot application, developers can use ________ to profile and monitor the application in real-time.
- Actuator
- JUnit
- Mockito
- Spock
To optimize the performance of a Spring Boot application, developers can use "Actuator" to profile and monitor the application in real-time. Spring Boot Actuator provides various production-ready features, including endpoints for monitoring and managing the application. These endpoints can be used to gather metrics, health information, and other runtime data, helping developers identify and address performance issues.
Which of the following annotations enables Auto Configuration in a Spring Boot application?
- @ComponentScan
- @Configuration
- @EnableAutoConfiguration
- @SpringBootApplication
The @EnableAutoConfiguration annotation enables Auto Configuration in a Spring Boot application. It triggers the automatic configuration of beans and components based on the project's dependencies and classpath. @SpringBootApplication is a meta-annotation that includes @EnableAutoConfiguration along with other annotations. @Configuration is used to define Java-based Spring configurations, and @ComponentScan is used for component scanning. They are not directly related to enabling Auto Configuration.
You notice that a Spring Boot application is experiencing high latency. How would you go about identifying and resolving the performance bottlenecks in the application?
- Use a profiling tool like VisualVM to analyze thread dumps.
- Increase the heap size of the JVM.
- Disable logging to reduce overhead.
- Add more physical memory to the server.
Option 1 is correct. Profiling tools like VisualVM can capture and analyze thread dumps, helping identify performance bottlenecks by showing which threads are causing delays. Increasing heap size or disabling logging may not directly address the root cause of high latency. Adding more physical memory could help with memory-related issues but may not solve latency problems.
In Mockito, to ensure that a mocked method was called with specific arguments, you would use the _____ method.
- assert
- check
- confirm
- verify
In Mockito, you can use the verify method to ensure that a mocked method was called with specific arguments. This is helpful for verifying that your code under test interacts with the mocked dependencies as expected.