How can back pressure be handled in a reactive stream in Spring Boot?

  • By using the collect operator.
  • By using the onBackpressureBuffer operator.
  • By using the retry operator.
  • By using the subscribe operator.
In Spring Boot's reactive streams, back pressure can be handled by using operators like onBackpressureBuffer. Back pressure is a mechanism that allows consumers to signal producers to slow down when they are overwhelmed with data. The onBackpressureBuffer operator is used to buffer excess items when the downstream subscriber can't keep up, preventing data loss and allowing the system to handle the flow of data efficiently.

What is the significance of Garbage Collection optimization in Spring Boot, and how can it impact application performance?

  • Garbage Collection has no impact on Spring Boot.
  • It can reduce memory usage.
  • It improves database performance.
  • It speeds up network communication.
Garbage Collection optimization is significant in Spring Boot because it can reduce memory usage. Inefficient garbage collection can lead to increased memory consumption, longer pauses, and application slowdowns. By optimizing garbage collection settings and strategies, you can reduce memory overhead, minimize pause times, and improve overall application performance. Garbage Collection does not directly impact database performance or network communication speed in Spring Boot applications.

In Spring Boot, which module enables the development of reactive applications?

  • spring-boot-starter-data-jpa
  • spring-boot-starter-security
  • spring-boot-starter-web
  • spring-webflux
In Spring Boot, the module that enables the development of reactive applications is spring-webflux. This module provides a foundation for building reactive, non-blocking applications. It includes support for creating reactive RESTful services and interacting with reactive data sources. Reactive programming is particularly useful for handling high concurrency and low latency scenarios.

integrate a custom authentication provider in Spring Security for implementing a custom authentication mechanism?

  • Extend the AbstractAuthenticationProcessingFilter class and override the attemptAuthentication method to handle custom authentication logic.
  • Modify the application.properties file to define custom authentication providers.
  • Add a custom AuthenticationProvider bean in the Spring application context and configure it in the security configuration.
  • Use the @CustomAuth annotation to specify custom authentication for specific controller methods.
To integrate a custom authentication provider in Spring Security, you should add a custom AuthenticationProvider bean to the Spring application context and configure it in the security configuration. This allows Spring Security to use your custom logic for authentication. Options 1 and 4 are not correct; they do not represent the standard way of integrating custom authentication providers. Option 2 is also incorrect as authentication providers are typically configured programmatically, not in properties files.

In Spring Security, how can you implement method-level security annotations?

  • Use the @MethodSecurity annotation to secure methods.
  • Apply @PreAuthorize and @PostAuthorize annotations.
  • Use @EnableMethodSecurity with @Configuration class.
  • Define method-level security in the application.properties file.
Method-level security annotations in Spring Security are implemented by using @EnableMethodSecurity in a @Configuration class and applying @PreAuthorize and @PostAuthorize annotations on methods. Options 1 and 4 are incorrect, while Option 2 is partially correct but not the recommended approach.

When defining a global exception handler in Spring Boot, you can use the _____ argument to access the details of the occurred exception.

  • Exception
  • Error
  • Throwable
  • ExceptionDetails
When defining a global exception handler in Spring Boot, you can use the Throwable argument in the exception handling method to access the details of the occurred exception. This argument allows you to inspect and respond to exceptions in a generic way. The other options do not represent the correct argument type for accessing exception details.

When implementing caching in Spring Boot, how can you handle cache concurrency?

  • By using a ConcurrentCacheManager as the cache manager.
  • By setting the spring.cache.concurrency property in the application.properties file.
  • By using the @Cacheable annotation with a sync attribute.
  • By implementing custom synchronization logic in your code.
To handle cache concurrency in Spring Boot, you can use the @Cacheable annotation with a sync attribute set to true. This ensures that cacheable methods are synchronized, preventing multiple threads from recomputing the same cached value concurrently. The other options are not standard approaches to handling cache concurrency in Spring Boot, and using a ConcurrentCacheManager is not a built-in feature of Spring Boot's caching framework.

Which annotation is primarily used for writing integration tests in Spring Boot applications?

  • @Autowired
  • @Component
  • @RunWith(SpringRunner.class)
  • @SpringBootTest
The @SpringBootTest annotation is primarily used for writing integration tests in Spring Boot applications. It loads the complete Spring application context, allowing you to perform tests in a real Spring environment.

Which of the following is true about the deleteById method of a JpaRepository?

  • It deletes an entity by its primary key and returns the deleted entity.
  • It deletes all entities in the repository and returns the number of deletions.
  • It marks the entity as "deleted" but does not physically remove it from the database.
  • It is not a standard method provided by JpaRepository.
The deleteById method of a JpaRepository deletes an entity by its primary key and returns the deleted entity. This method is a convenient way to remove a specific entity from the database. The other options do not accurately describe the behavior of this method, as it neither deletes all entities nor marks an entity as "deleted" without removing it from the database.

In a Spring Boot application, the _____ annotation is used to bind the value of a method parameter to a named cookie value.

  • @Cookie
  • @CookieParam
  • @CookieValue
  • @ValueCookie
In a Spring Boot application, the @CookieValue annotation is used to bind the value of a method parameter to a named cookie value. This allows you to access and use cookies sent by the client in your controller methods. It simplifies the process of working with cookies in a Spring Boot application.