20 Spring Reactive Interview Questions and Answers

If you’re interviewing for a position that uses the Spring Reactive framework, you can expect to be asked about your experience and knowledge of the framework. In this article, we’ll review some of the most common Spring Reactive interview questions so you can be prepared to answer them confidently.

Spring Reactive Interview Questions and Answers

Here are 20 commonly asked Spring Reactive interview questions and answers to prepare you for your interview:

1. What are the main differences between Spring and Spring Boot?

The main difference between Spring and Spring Boot is that Spring Boot is designed to simplify the process of creating and deploying Spring-based applications. Spring Boot takes an opinionated approach to application configuration, meaning that it provides a set of default configurations that can be used to get an application up and running quickly. Spring, on the other hand, is a more general-purpose framework that can be used to build any type of application.

2. What is reactive programming?

Reactive programming is a programming paradigm that is concerned with data streams and the propagation of change. This means that instead of dealing with individual pieces of data, reactive programming deals with data streams. These data streams can be created from various sources, including user input, sensors, and databases. Reactive programming is often used in event-driven applications, where changes to data can trigger events that cause the application to respond in some way.

3. What do you understand about non-blocking I/O in context with reactive programming?

Non-blocking I/O essentially means that a thread is not blocked waiting for an I/O operation to complete. This can be beneficial in reactive programming because it allows for a more responsive and concurrent system.

4. How does event looping work in JavaScript?

Event looping in JavaScript is a process whereby the engine continually checks for events and then executes the associated code for those events. This can happen in a number of ways, but typically it is done via a callback function that is associated with the event.

5. Can you explain what a callback function is in Node.js?

A callback function is a function that is passed as an argument to another function. The callback function is then invoked inside of the other function. Callback functions are often used to handle asynchronous operations.

6. What’s the difference between an asynchronous and synchronous call?

Asynchronous calls do not block the caller, while synchronous calls do. Asynchronous calls can be made without waiting for a response, while synchronous calls must wait for a response before continuing.

7. What is the API Gateway pattern and how does it relate to Spring WebFlux?

The API Gateway pattern is a design pattern that is used to provide a single point of entry for all requests to an application. This can be useful for load balancing, security, and other purposes. In the context of Spring WebFlux, the API Gateway can be used to route requests to the appropriate controller.

8. What is the Reactive Manifesto?

The Reactive Manifesto is a set of principles for building reactive systems. These systems are responsive, resilient, elastic, and message-driven.

9. What do you mean by the term “backpressure” in context with reactive programming?

Backpressure is a mechanism for managing the flow of data in a reactive stream. It is used to ensure that a faster producer does not overwhelm a slower consumer by providing a way for the consumer to control the rate at which data is produced.

10. What are some benefits of using the Actor model for building applications?

There are several benefits to using the Actor model for building applications. First, it allows for a high degree of parallelism and concurrency. This can lead to better performance and scalability. Second, it can help to improve the modularity and maintainability of an application by allowing different parts of the application to be isolated from each other. Finally, it can make it easier to handle failures, since each actor can be designed to deal with failures in a local and isolated manner.

11. What are some common use cases of reactive programming?

Reactive programming is often used for event-driven applications, where the program needs to respond to events as they happen. This can include things like user input, network traffic, or changes in data. Reactive programming can also be used for streaming data, where data is processed as it comes in, rather than all at once.

12. What are some design patterns that can be used when developing microservices based on the actor model?

There are a few design patterns that can be used when developing microservices based on the actor model. One is the use of the event-based communication pattern, which can be used to send messages between actors in a system. Another is the use of the message passing pattern, which allows for asynchronous communication between actors.

13. What are some limitations of the actor model?

One potential limitation of the actor model is that it can be difficult to debug concurrent systems. Additionally, the actor model relies on message passing, which can introduce latency into the system.

14. What problems is Spring WebFlux designed to address?

Spring WebFlux is designed to address the problem of too much blocking I/O in traditional web applications. When a traditional web application receives a request, it often has to wait for a response from a database or another external service before it can generate a response to the client. This can lead to long delays and a poor user experience.

Spring WebFlux uses a non-blocking I/O model that allows it to handle a large number of concurrent requests without waiting for responses from external services. This makes it much more responsive and scalable than traditional web applications.

15. What’s your understanding of the Reactor and Project Reactor frameworks?

Reactor is a Java framework for building reactive, non-blocking applications. It is based on the Reactive Streams specification. Project Reactor is the implementation of the Reactor framework.

16. Can you tell me more about Akka, Vert.x, and Ratpack?

Akka is a toolkit for building concurrent, distributed, and fault-tolerant applications on the JVM. Vert.x is a toolkit for building reactive applications on the JVM. Ratpack is a toolkit for building scalable, non-blocking applications on the JVM.

17. Can you give me some examples of reactive APIs that are already available in Java?

There are a few reactive APIs that are already available in Java. Some of these include the Java 8 Stream API, the RxJava library, and the Reactor library.

18. What is Netty and how does it help with reactive systems?

Netty is a low-level network programming library that can be used to create high-performance, reactive applications. It provides a clean, easy-to-use API that can be used to build scalable, concurrent applications. Netty is particularly well-suited for building event-driven, non-blocking applications.

19. What do you understand about back pressure and flow control in context with reactive systems?

Back pressure is a form of flow control that is used to ensure that a reactive system does not become overwhelmed with too much data. When data starts to come in faster than the system can process it, the back pressure mechanism is used to throttle the data so that it can be processed more slowly. This helps to prevent the system from becoming overloaded and ensures that data is processed correctly.

20. What are the different types of resources or media types supported by Spring WebFlux?

Spring WebFlux supports a variety of resources or media types, including but not limited to:

– JSON
– XML
– YAML
– Multipart Form Data
– Binary Data