How can you enable transaction management in a Spring Boot application?
- By annotating methods or classes with @Transactional.
- By configuring transactions in the application.properties file.
- By using the @EnableTransactionManagement annotation.
- Spring Boot enables transaction management by default.
You can enable transaction management in a Spring Boot application by using the @EnableTransactionManagement annotation. This annotation tells Spring to enable transactional behavior for annotated methods. While you can also annotate methods or classes with @Transactional to specify transactional behavior, you need to enable transaction management globally with @EnableTransactionManagement. Spring Boot does not enable transaction management by default, and configuring transactions in application.properties is not a common approach for enabling transaction management.
You are tasked with developing a Spring Boot application that integrates with multiple external APIs. How would you implement exception handling to manage failures and ensure that informative error messages are relayed back to the user?
- Implement a retry mechanism for API calls, and return HTTP status codes along with descriptive error messages in the response.
- Log all exceptions internally without providing any error messages to the user.
- Return generic error messages without any HTTP status codes to avoid exposing internal details.
- Implement a global exception handler that returns standardized error responses with clear error messages and appropriate HTTP status codes.
When integrating with external APIs in a Spring Boot application, it's crucial to implement a global exception handler (Option 4) to manage failures. This handler should return standardized error responses with clear error messages and appropriate HTTP status codes, ensuring informative messages are relayed back to the user. Implementing a retry mechanism (Option 1) is a good practice, but it should be combined with proper error handling. Options 2 and 3 are not recommended as they either log errors internally or provide generic and uninformative error messages to users.
A Spring Boot application is facing frequent OutOfMemoryErrors. Describe the steps you would take to diagnose the root cause and mitigate this issue.
- Enable garbage collection logging with JVM flags.
- Increase the number of application instances.
- Disable the use of Spring beans.
- Reduce the number of threads in the application.
Option 1 is correct. Enabling garbage collection logging with JVM flags allows you to analyze memory usage patterns and identify memory leaks or excessive memory consumption, which are common causes of OutOfMemoryErrors. Increasing the number of application instances may exacerbate the issue if it's related to memory consumption. Disabling Spring beans or reducing threads may not be suitable solutions for addressing OutOfMemoryErrors.
What are the considerations and best practices for using @Primary in projects with multiple beans and dependencies?
- Use @Primary to define a default bean when no qualifier is specified.
- Avoid using @Primary when there are multiple beans of the same type.
- Always use @Primary to ensure the bean is selected in all cases.
- Use @Primary only with setter-based injection, not constructor injection.
In projects with multiple beans and dependencies, @Primary should be used to define a default bean when no qualifier is specified. This provides a clear choice when there is ambiguity. However, it should be used judiciously, especially when there are multiple beans of the same type. It should not be overused, as it can lead to unexpected behavior. The other options do not accurately represent best practices for using @Primary.
To customize the storage and retrieval of cache in Spring Boot, a developer can implement the _____ interface.
- CacheableManager
- CacheResolver
- CacheProvider
- CacheCustomizer
In Spring Boot, to customize the storage and retrieval of cache, a developer can implement the CacheResolver interface. This interface provides methods to resolve cache instances dynamically. The other options are not standard interfaces for customizing caching in Spring Boot.
In Spring, what is the process of supplying an external dependency to an object called?
- Bean Inversion
- Bean Registration
- Dependency Injection
- Dependency Wiring
The process of supplying an external dependency to an object in Spring is called "Dependency Injection." It involves injecting or providing the required dependencies to an object rather than having the object create them itself, promoting loose coupling and easier testing.
What is the primary purpose of Auto Configuration in Spring Boot?
- Controlling database access.
- Enhancing security.
- Managing network connections.
- Reducing application complexity.
The primary purpose of Auto Configuration in Spring Boot is to reduce application complexity. It achieves this by automatically configuring application components based on dependencies and classpath settings. This simplifies the development process by eliminating much of the manual configuration that would otherwise be required. While security, database access, and network connections are important aspects of an application, they are not the primary focus of Auto Configuration.
In a Spring Boot application, the _____ annotation allows the conditional caching of method return values based on the evaluation of a SpEL expression.
- @CacheConfig
- @CacheEvict
- @Cacheable
- @Caching
In a Spring Boot application, the @Cacheable annotation is used to enable conditional caching of method return values based on the evaluation of a SpEL (Spring Expression Language) expression. By using this annotation, you can specify when a method's result should be cached, which is helpful for optimizing performance in certain scenarios.
In reactive programming with Spring Boot, how can you handle errors in a reactive stream?
- By avoiding errors altogether through careful coding.
- By relying on the default error handling provided by Spring Boot.
- By using the onError operator and other error-handling operators provided by Project Reactor.
- By using try-catch blocks around reactive operators.
In reactive programming with Spring Boot, you can handle errors in a reactive stream by using the onError operator and other error-handling operators provided by Project Reactor. These operators allow you to define how to react to errors within the stream, whether it's by logging, retrying, switching to a fallback stream, or propagating the error to the subscriber. This enables robust error handling and recovery strategies in reactive applications.
To inject mock objects into the tested object in a Spring Boot unit test, the _____ annotation is used with Mockito.
- @Autowired
- @InjectMocks
- @MockBean
- @MockitoInject
In Spring Boot unit testing with Mockito, you use the @InjectMocks annotation to inject mock objects into the object being tested. This allows you to control the behavior of dependencies during testing.