To execute a task immediately after the ApplicationContext has been started in a Spring Boot application, you can implement a custom event listener that listens for the ContextRefreshedEvent. This event is raised when the ApplicationContext is fully initialized and ready to use. You can then execute your task in response to this event.

Option 1 is correct. Profiling production Spring Boot applications can be done using tools like VisualVM or Java Flight Recorder without significant performance impact. These tools provide insights into application behavior and resource usage. Disabling all logging (Option 2) is not a recommended approach as logging is essential for debugging and monitoring. Increasing memory allocation (Option 3) may not help with profiling. Running load tests concurrently (Option 4) can further impact performance and is not ideal for profiling.

To create a custom Auto Configuration that provides beans conditionally based on the presence of a specific library on the classpath, you should use the @ConditionalOnClass annotation. Specify the library's class in the annotation's value attribute. This approach ensures that the beans are only created when the specified class is available on the classpath, ensuring the required conditions are met.

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 @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.

Among the provided options, the @Autowired annotation is specifically used for injecting dependencies on setter methods in Spring. When you apply @Autowired to a setter method, Spring will automatically inject the required dependencies into that setter method. The other annotations have different purposes, such as @Inject and @Resource are more generic dependency injection annotations, and @Setter is not a standard Spring annotation for dependency injection.

The correct option is Option 2: Spring Boot Actuator. Spring Boot Actuator provides built-in production-ready features for monitoring and profiling Spring Boot applications. It exposes various endpoints that can be used for metrics, health checks, and application-specific information. These endpoints can be accessed via HTTP, JMX, or other protocols, allowing you to gather important insights into the behavior and performance of your Spring Boot application. Other tools like Visual Studio Code, Postman, and Apache Tomcat are not primarily used for profiling Spring Boot applications.

The correct format to specify the required authority using the @Secured annotation is @Secured("ROLE_ADMIN"). The "ROLE_" prefix is typically used to specify roles. The other options are not the correct format.

To ensure data consistency in a Spring Boot application using Spring Data JPA, it's best to use declarative transaction management with the @Transactional annotation. This allows you to specify transaction boundaries at the method level, ensuring that each service method operates within a transaction. Implementing programmatic transaction management or disabling transactions can lead to data inconsistency issues. Distributed transactions are complex and typically used in multi-database scenarios.

In Spring Boot's project structure, the application properties file should be placed in the "src/main/resources" directory with the filename "application.properties." This is the standard location for configuration properties in a Spring Boot application. Placing it elsewhere or with a different name may require custom configuration.