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Reactive Streams interview questions

Backpressure Strategies, Blocking the Event Loop, Functional Pipelines (flatMap), Non-Blocking I/O (Event Loops), Publisher and Subscriber, Thread-Per-Request Bottleneck

120 questions with answers and explanations · 120 flashcards

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Questions (page 3 of 3)

  1. Why is calling a blocking JDBC repository directly from a WebFlux event-loop thread dangerous?Multiple choiceHard
  2. Why is the 'flatMap' operator significant in a reactive stream?Multiple choiceMedium
  3. How does backpressure help manage data flow in a Reactive Streams system?Multiple choiceHard
  4. Which method would you use on a Flux to handle errors gracefully?Multiple choiceEasy
  5. Which component in Reactive Streams requests data from a Publisher?Multiple choiceEasy
  6. How would you explain a significant debugging challenge when using WebFlux compared to Java 21 Virtual Threads in an interview?Multiple choiceHard
  7. Why might you bound flatMap() concurrency when calling a downstream pricing service?Multiple choiceHard
  8. In a system using Project Reactor, what could be a consequence of using blocking operations on the event loop thread?Multiple choiceHard
  9. How would you explain a key challenge when debugging WebFlux applications compared to Java 21 Virtual Threads in an interview?Multiple choiceHard
  10. Why does the Subscriber in a Reactive Streams setup matter in this design?Multiple choiceMedium
  11. When using Project Reactor, why is it important to avoid blocking operations on the event loop?Multiple choiceMedium
  12. Why does a 'Subscriber' in the Reactive Streams specification matter in this design?Multiple choiceMedium
  13. In Project Reactor, what is the difference between Mono and Flux?Multiple choiceHard
  14. In the context of Project Reactor, what is the primary purpose of the 'publishOn' method?Multiple choiceMedium
  15. What potential issue arises when blocking operations are executed within a non-blocking event loop?Multiple choiceHard
  16. How does WebFlux handle database queries to maintain non-blocking behavior?Multiple choiceMedium
  17. How does the Flux type in Project Reactor differ from Mono?Multiple choiceMedium
  18. Which function is preferable when transforming data within a reactive stream without changing its structure?Multiple choiceMedium
  19. When considering WebFlux for an e-commerce server, what is a primary benefit over traditional Spring MVC?Multiple choiceMedium
  20. How would you explain a key difference between using WebFlux and Virtual Threads for handling concurrency in an interview?Multiple choiceMedium