Reactive Programming in Java: Spring WebFlux & Testing

Name: Reactive Programming in Java: Spring WebFlux & Testing
Rating: 4.5 (33 reviews)

Build Reactive REST APIs, Master Unit and Integration Testing - Java, Spring Boot, WebFlux, REST, MongoDB, IntelliJ

Highest Rated

Created byRamesh Fadatare (Java Guides)

Last updated 6/2026

English

What you'll learn

Introduction to Reactive Programming in Java
Learn how to Use Spring WebFlux in Spring Boot App
Learn to Build Reactive CRUD REST APIs for Employee Management Project
Learn to Write Unit Tests for Reactive CRUD REST APIs
Learn to Write Integration Tests for Reactive CRUD REST APIs

Course content

5 sections • 34 lectures • 3h 33m total length

Introduction to Reactive Programming9:22
Reactive Stream Specifications4:30
Reactive Stream Workflow4:02
Understanding Project Reactor Mono and Flux13:07
Explore My 15+ Courses on Udemy Business – Don’t Miss Out!0:58

Introduction to Spring WebFlux4:01
Explore Spring WebFlux, a reactive web framework built on Spring Framework 5 and Project Reactor, for building reactive web apps and rest APIs using the reactive MongoDB driver.
Spring Boot WebFlux Application Architecture2:25
Architect a Spring Boot webflux app with controller, service, repository layers, where methods return mono or flux and use a MongoDB to build reactive employee rest CRUD api.
Deploy MongoDB in Docker Container6:03
Create and Set up Spring Boot Project in IntelliJ IDE6:36
Set up a Spring Boot project in IntelliJ using Spring Initializr, Maven, Java 17, and Spring Boot 3.0.1, and add the Spring Reactive Web, MongoDB Reactive, and Lombok dependencies.
Create Employee Entity4:47
Create EmployeeRepository and Understanding Internals5:13
Create EmployeeDto and EmployeeMapper4:02
Build Reactive Add Employee REST API13:54
Build Reactive Get Employee REST API6:34
Build Reactive Get All Employees REST API5:51
Implement a reactive get all employees rest API by wiring the service to return a flux of employee DTOs, mapping from entities, and exposing a get endpoint.
Build Reactive Update Employee REST API9:28
Build a reactive update employee REST API with Spring WebFlux and MongoDB, implementing the service and controller layers with Mono, flatMap, and DTO mapping to update records.
Build Reactive Delete Employee REST API5:56
Download Source Code of this Section0:04
Section Quiz: Test Yourself

Overview of Testing CRUD Reactive REST APIs using WebFlux6:03
Unit Test Add Employee REST API13:49
Unit Test Get Employee REST API7:28
Unit Test Get All Employees REST API8:28
Unit test the get all employees REST API by mocking the employee service to return a flux of employee DTOs, then verify 200 response with JSON list of employees.
Unit Test Update Employee REST API8:28
Unit Test Delete Employee REST API5:32
Download source code of this section0:04

Write a Integration Test for Add Employee REST API11:04
Write a Integration Test for Get Employee REST API6:48
Write a Integration Test for Get All Employees REST API6:13
Refactor the Code to Use @BeforeEach Annotation4:02
Write a Integration Test for Update Employee REST API7:29
Write a Integration Test for Delete Employee REST API3:42
Download Source Code of this Section0:04
Quiz on Spring WebFlux Unit and Integration Testing

Requirements

Java programming
Good to know how to use IntelliJ IDEA
Familiar with Spring Boot
Good to know MongoDB

Description

In this course, you will learn how to build and Unit test Reactive REST APIs for Employee Management System projects using Java, Spring Boot, WebFlux, REST, MongoDB, and IntelliJ IDEA.

Learn to build powerful Reactive REST APIs using Java, Spring Boot, and WebFlux in this beginner-friendly course. You'll discover how to handle data in a reactive way, making your applications more efficient and scalable. We’ll work with MongoDB for data storage, ensuring your projects are up-to-date with modern web development practices.

Testing is a key part of building reliable software, so you’ll also learn how to write clear and effective Unit and Integration tests. Using tools like JUnit and Mockito in IntelliJ IDEA, you'll gain the skills to ensure your code works as expected.

By the end of this course, you'll have the confidence to build and test reactive applications, setting you apart in today’s tech world.

Tools and Technologies Used:

Java 17+
Spring Boot 3
Spring WebFlux
Project Reactor
Maven
IntelliJ IDEA
MongoDB
Docker

What You’ll Learn:

How to build Reactive REST APIs with Spring Boot and WebFlux.
How to use MongoDB for reactive data handling.
The basics of reactive programming in Java.
How to write Unit tests for Reactive REST APIs.
How to create and run Integration tests for Reactive REST APIs.
How to use IntelliJ IDEA for coding and testing.

Who this course is for:

This course is for beginners who want to learn how to build Reactive REST APIs and master writing Unit and Integration tests.

Reactive Programming in Java: Spring WebFlux & Testing

What you'll learn

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Course content

Introduction to Reactive Programming5 lectures • 32min

Spring WebFlux - Reactive CRUD REST APIs for Employee Management13 lectures • 1hr 15min

Introduction to Testing2 lectures • 17min

Spring WebFlux - Unit Tests for Reactive CRUD REST APIs7 lectures • 50min

Spring WebFlux - Integration Tests for Reactive CRUD REST APIs7 lectures • 39min

Requirements

Description

Who this course is for: