Micronaut JVM Framework

Odysseas MourtzoukosMarch 8th, 2023Last Updated: March 9th, 2023

0 157 3 minutes read

In today’s world of cloud computing, microservices, and serverless architectures, building applications that are scalable, lightweight, and efficient has become essential. This is where Micronaut comes into play, offering developers a modern, JVM-based framework that simplifies the process of building microservices and serverless applications. In this article, we will take a closer look at Micronaut and explore its features and benefits for building microservices and serverless applications.

1. What Is Micronaut

Micronaut is a modern, JVM-based full-stack framework for building modular, easy-to-test, and high-performance microservices and serverless applications. It was first released in 2018 and has gained popularity in the Java ecosystem due to its innovative features and reduced startup times.

Micronaut leverages compile-time dependency injection, AOP, and native-image compilation to achieve fast startup times and a low memory footprint. It also supports reactive programming and cloud-native architectures through integrations with popular technologies like Spring, Kafka, gRPC, and more.

Micronaut also comes with a range of tools and features to streamline development, such as command-line tools, automatic configuration, and support for various data formats and databases.

2. Main Features

The main features of Micronaut are:

Lightweight and Fast: It has a low memory footprint and fast startup times due to its use of compile-time dependency injection and native image compilation.
Easy-to-test: Micronaut’s built-in testing features make it easy to write and run unit tests for your microservices.
Cloud-Native: It is designed for cloud-native architectures and has built-in support for Kubernetes, service discovery, and distributed tracing.
Reactive: It supports reactive programming with support for reactive streams and non-blocking I/O.
Multiple Languages: It is not limited to Java and supports several languages like Groovy and Kotlin.
Easy Configuration: It provides automatic configuration for many common scenarios, and its YAML-based configuration files make it easy to configure your microservices.
Web Framework: It has a powerful web framework that supports MVC, serverless functions, and non-blocking HTTP requests.
Database Integration: It provides easy integration with popular databases like MySQL, MongoDB, and Cassandra.
Security: It provides features for securing your microservices, including support for OAuth 2.0 and JWT.
Tooling: It comes with a range of command-line tools, including a CLI, a test runner, and a serverless function deployment tool.

3. Installing Micronaut

To install Micronaut, you need to have Java installed on your machine. You can follow these steps to install the framework

3.1 Command Prompt

Download and install the latest version of Java on your machine.
Open a terminal or command prompt and enter the following command to install the Micronaut CLI:

$ curl -Lo /usr/local/bin/mn https://github.com/micronaut-projects/micronaut-starter/releases/download/v3.1.1/mn-macos-x86_64 && chmod +x /usr/local/bin/mn

Note: Replace the download URL with the latest version available.

Verify that the Micronaut CLI is installed correctly by entering the following command:

$ mn --version

You can now create a new project by entering the following command:

$ mn create-app com.example.myapp --lang=java

Note: Replace “com.example.myapp” with your desired package name.

Once the project is created, you can navigate to the project directory and build the project using the following command:

$ ./gradlew build

Note: If you prefer to use Maven instead of Gradle, replace “./gradlew” with “mvn”.

3.2 Gradle

Create a new Gradle project by running the following command:

$ gradle init --type java-application

Add the Micronaut dependencies to your project by adding the following code to your build.gradle file

plugins {
    id 'com.github.johnrengelman.shadow' version '7.0.0'
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'io.micronaut:micronaut-http-server-netty:3.1.1'
    implementation 'io.micronaut:micronaut-runtime:3.1.1'
    implementation 'javax.annotation:javax.annotation-api:1.3.2'
}

shadowJar {
    mergeServiceFiles()
}

Note: Replace the version numbers with the latest version available.

Create a new class for your Micronaut application by adding the following code to your project

import io.micronaut.runtime.Micronaut;

public class Application {
    public static void main(String[] args) {
        Micronaut.run(Application.class, args);
    }
}

Build your project by running the following command:

$ gradle shadowJar

Note: The shadowJar task builds a single fat jar that includes all the dependencies needed to run your Micronaut application.

Run your application by executing the following command:

$ java -jar build/libs/<your-project-name>-all.jar

4. Conclusion

In conclusion, Micronaut is a modern, lightweight, and fast JVM-based framework that simplifies the process of building microservices and serverless applications. Its numerous features, including cloud-native support, reactive programming, multiple language support, easy configuration, web framework, database integration, security, and tooling make it an excellent choice for developing microservices and serverless applications. It can be installed using the CLI or a build tool like Gradle or Maven, and it’s easy to get started with creating a basic application. Also, developers can focus on writing business logic without worrying about the infrastructure, resulting in faster development and deployment times.