Micronaut with VS Code: Recommended Setup

Micronaut is a modern, lightweight Java framework. Many developers love using VS Code because it’s free, fast, and full of useful extensions. In this guide, we will go step-by-step to set up Micronaut development in Visual Studio Code (VS Code) in a simple and beginner-friendly way.

Why Use Micronaut with VS Code?

Lightweight IDE: Faster startup compared to heavy IDEs.
Great extensions: Supports Java, Micronaut, debugging, and more.
Cross-platform: Works on Windows, Mac, and Linux.
Free and open-source

Combining Micronaut and VS Code makes microservice development smooth and efficient.

Prerequisites

Before starting, make sure you have:

Java 21 JDK
- Download from Adoptium or Oracle.
Micronaut CLI (Optional but useful)
- Install using SDKMAN: sdk install micronaut
- Or download from Micronaut.io.
Visual Studio Code
- Download and install from VS Code.

Step 1: Install Required VS Code Extensions

Open VS Code and go to the Extensions panel (left sidebar).

Search and install these extensions:

Extension Name	Purpose
Java Extension Pack	Provides Java support, debugging, Maven, Gradle
Micronaut Tools	Adds Micronaut-specific support
Gradle for Java	Gradle support for builds
Docker (optional)	If you plan to containerize apps

You can also install the Java Extension Pack directly:

ext install vscjava.vscode-java-pack

Step 2: Create a New Micronaut Project

Using Micronaut Launch

Go to Micronaut Launch.
Choose:
- Language: Java
- Java Version: 21
- Build Tool: Gradle or Maven
- Features: Add features like http-server, management, testcontainers if needed.
Generate and download the zip file.
Extract it and open the folder in VS Code.

Using Micronaut CLI (optional)

If you installed Micronaut CLI:

mn create-app com.kscodes.micronautvscode --java-version 21

Open the generated folder in VS Code:

code com.kscodes.micronautvscode

Step 3: Configure Java in VS Code

VS Code should automatically detect Java. If not:

Go to Settings > Java: Home.
Set it to your Java 21 JDK path.

Step 4: Build and Run Your Micronaut App

Build with Gradle

Use the integrated terminal (Ctrl+`) in VS Code:

./gradlew build

Run the App

./gradlew run

Alternatively, you can use VS Code’s Run and Debug option for better control.

Step 5: Create Your First Controller

Let’s create a simple Hello World REST API.

File: src/main/java/com/kscodes/micronautvscode/HelloController.java

package com.kscodes.micronautvscode;

import io.micronaut.http.annotation.*;

@Controller("/hello")

public class HelloController {

@Get("/{name}")

public String sayHello(String name) {

return "Hello, " + name + "!";

}

Test it by opening:

http://localhost:8080/hello/World

You should see:

Hello, World!

Step 6: Debugging in VS Code

Open the Run and Debug panel.
Click create a launch.json file.
Select Java as environment.
VS Code will generate the config.
Click Run to start debugging.

Step 7: Enable Virtual Threads (Java 21 Feature)

In application.yml:

micronaut:

executors:

io:

type: virtual

This allows Micronaut to use Java 21 virtual threads.

Step 8: Running Tests

Micronaut supports JUnit 5 out of the box.

File: src/test/java/com/kscodes/micronautvscode/HelloControllerTest.java

package com.kscodes.micronautvscode;

import io.micronaut.test.extensions.junit5.annotation.MicronautTest;

import org.junit.jupiter.api.Test;

import jakarta.inject.Inject;

import io.micronaut.http.client.HttpClient;

import io.micronaut.http.client.annotation.Client;

import static org.junit.jupiter.api.Assertions.*;

@MicronautTest

class HelloControllerTest {

@Inject

@Client("/")

HttpClient client;

@Test

void testHelloEndpoint() {

String response = client.toBlocking().retrieve("/hello/World");

assertEquals("Hello, World!", response);

}

Run tests using VS Code’s Testing panel.

Summary

Install Java 21, Micronaut CLI, and VS Code.
Add Java and Micronaut extensions to VS Code.
Create, build, run, and debug Micronaut apps directly inside VS Code.
Leverage Java 21 features like virtual threads.

Useful Links

Stay tuned for more beginner-friendly Micronaut tutorials!