Spring Boot Spring Boot WebFlux and Reactive Programming 2

Question 1

In Spring WebFlux, what is the role of the `ServerRequest` object in a `HandlerFunction`?

Accepted Answer

It encapsulates the HTTP request including headers, body, and path variables

Answer

`ServerRequest` provides access to the HTTP method, URI, headers, and body of an incoming request inside a `HandlerFunction`.

Question 2

Which operator would you use on a `Flux` to transform each element asynchronously using another reactive publisher?

Accepted Answer

flatMap

Answer

`flatMap` maps each element to a `Publisher` and merges the results, making it ideal for asynchronous transformations in reactive pipelines.

Question 3

How do you enable reactive repository support for MongoDB in Spring Boot?

Accepted Answer

Add spring-boot-starter-data-mongodb-reactive

Answer

Adding `spring-boot-starter-data-mongodb-reactive` pulls in the reactive MongoDB driver and auto-configures `ReactiveMongoTemplate` and reactive repositories.

Question 4

What is backpressure in the context of reactive streams?

Accepted Answer

A signal from subscriber to publisher to slow down data emission

Answer

Backpressure is the ability of a subscriber to signal upstream publishers to reduce the rate of data emission, preventing out-of-memory errors.

Question 5

Which WebFlux annotation marks a class as a reactive REST controller that returns reactive types?

Accepted Answer

@RestController

Answer

`@RestController` works in both Spring MVC and Spring WebFlux; when return types are `Mono` or `Flux`, Spring WebFlux handles them reactively.

Spring Boot Practice Test

Spring Boot Practice Test

Spring Boot Spring Boot WebFlux and Reactive Programming 2