Spring Boot Building RESTful Services 4

Question 1

What is the purpose of content negotiation in a Spring REST API?

Accepted Answer

Selecting the response format based on the client's Accept header

Answer

Content negotiation allows the server to serve different representations (JSON, XML, etc.) of the same resource based on the client's Accept header.

Question 2

In Spring Boot, what annotation combination makes a class a REST controller that also serves as a Spring component?

Accepted Answer

@RestController

Answer

@RestController is a composed annotation that combines @Controller (component stereotype) and @ResponseBody, registering the class as a bean and enabling automatic response serialization.

Question 3

What does Spring's @RequestBody annotation do when used on a controller method parameter?

Accepted Answer

Deserializes the HTTP request body into a Java object

Answer

@RequestBody instructs Spring to read the HTTP request body and deserialize it into the annotated parameter type using the configured HttpMessageConverter.

Question 4

Which HTTP method is idempotent but NOT safe, meaning it can modify server state but repeated calls produce the same result?

Accepted Answer

PUT

Answer

PUT is idempotent because calling it multiple times with the same payload results in the same server state, but it is not safe because it modifies the resource.

Question 5

What happens when you annotate a @RestController method parameter with @Valid and the validation fails?

Accepted Answer

Spring throws MethodArgumentNotValidException and returns HTTP 400

Answer

When bean validation fails on a @RequestBody annotated with @Valid, Spring throws MethodArgumentNotValidException, which by default maps to a 400 Bad Request response.

Spring Boot Practice Test

Spring Boot Practice Test

Spring Boot Building RESTful Services 4