Spring Framework Spring Framework 4

Question 1

What happens when you annotate a Spring bean method with @PostConstruct?

Accepted Answer

It runs the method once after dependency injection is complete

Answer

@PostConstruct marks an initialization method that Spring calls after the bean is fully constructed and all dependencies are injected.

Question 2

Which interface should a Spring bean implement to perform cleanup when the application context is closed?

Accepted Answer

DisposableBean

Answer

DisposableBean provides a destroy() method that Spring calls when the container closes, allowing resource cleanup.

Question 3

What is the purpose of Spring's @Profile annotation?

Accepted Answer

To activate beans only when a specific environment profile is active

Answer

@Profile restricts bean registration to specific environment profiles (e.g., 'dev', 'prod') set via spring.profiles.active.

Question 4

In Spring WebFlux, what is a Mono?

Accepted Answer

A publisher that emits 0 or 1 item asynchronously

Answer

Mono is a reactive publisher from Project Reactor that represents a single asynchronous value or an empty result.

Question 5

Which Spring annotation is used to define a class as a Spring MVC controller that returns data directly instead of a view name?

Accepted Answer

@RestController

Answer

@RestController combines @Controller and @ResponseBody, so every method return value is serialized directly to the HTTP response.

Spring Framework Practice Test