initializr VS mockk

The best way, for generating a ready-to-run application in Java you can use the Spring Boot Initializr tool.

curl --location 'https://start.spring.io/starter.zip?type=maven-project&language=java&bootVersion=3.2.2&baseDir=ms-xcoffee&groupId=com.xcoffee&artifactId=ms-xcoffee&name=ms-xcoffee&description=Demo%20project%20for%20Spring%20Boot&packageName=com.xcoffee.ms-xcoffee&packaging=jar&javaVersion=21&dependencies=webflux%2Clombok%2Cvalidation' | tar -xzvf -

In this segment we will create a basic Spring boot app from Spring Initializer. Add the below dependencies:

Add the following MongoDB dependencies in your pom.xml or use spring initializer and select the Spring Data MongoDB dependency:

I created all of these applications using start.spring.io's REST API and HTTPie.

An easy way to create the skeleton project is to visit Spring Initializr, I set the Project to Gradle - Groovy, Language to Java, and add Spring Web dependency. Then it's just to generate the project and unpack it.

Create a new Spring Boot application using the Spring Initializr. You can use the web version or the curl command below. Use the default for most of the options. For the dependencies, select web, and okta. For the build tool, select Gradle.

I will start with a simple example of a cloud function, which is the same as a rest endpoint in the classical spring boot web application. You can create a project from your favorite IDE or from Spring Initliazr.

I would advise everyone to go the extra mile and update their entire spring boot version to the latest appropriate version. To find out what that is, simply go to https://start.spring.io.

The official suggests using dagger/hilt to inject them. However, they could be static based on the static ApplicationContext. Although Dagger/hilt aids in unit testing, mockk can accomplish this easily as well by modifying bytecode during run time. As for the stability, `mockk` has 5000+ stars on GitHub and keeps renewing.

We can create it as a class as MockK is able to mock final classes.

Mockk Documentation

Mockk is a rather new framework; it was originally designed for Kotlin, although it supports Java as well. Before mockito-kotlin was released, using Mockk was much easier and beneficial for Kotlin developers, but right now both these frameworks have nearly the same set of features and similar syntax. For example, assume that our function loadUsers is no longer synchronous, but rather suspended:

You can use mockkStatic for that, see docs. Also don't forget to unmockkStatic afterwards.

WARNING: reflective-mockk is currently powered by a reflective “hack” on mockK, and is thereby subject to removal/breakage by the mockK team at any time. If you enjoy this library & want it to be officially supported, post a comment saying so on this PR: https://github.com/mockk/mockk/pull/1005.

https://mockk.io/ is great, too.

Mockito does not work correctly with Kotlin types out of the box. Spring recommends using Mockk. There is also a special module for Mockito, which adds support for Kotlin - Mockito-Kotlin.