• What is Helidon?

• Helidon Flavors

  • What flavor shall I use?

• Prerequisites

• Next Steps

Helidon is a collection of Java libraries for writing microservices that run on a fast web core powered by Netty. It’s small, fast, and fun to use.

Helidon is open source under the Apache 2.0 license. Sources are available on GitHub.

Helidon is cloud-native ready. It provides fast start-up time and has low memory consumption and a small disk footprint. It also comes with a full observability stack out of the box including health checks, metrics, tracing and logging.

Helidon fully supports GraalVM native image allowing you to build a native executable from your Java application.

Helidon comes in two flavors: Helidon SE and Helidon MP. Think about these flavors as frameworks providing similar functionality but offering different developer experiences.

To help illustrate the differences, below are two samples implementing a simple RESTful service. One uses Helidon SE, the other Helidon MP.

Routing routing = Routing.builder()
    .get("/hello",
        (req, res) -> res.send("Hello World"))
    .build();

WebServer.create(routing)
    .start();

@Path("hello")
public class HelloWorld {
    @GET
    public String hello() {
        return "Hello World";
    }
}

What flavor shall I use?

Helidon requires Java and Maven. You might also need Docker and Kubernetes depending on how you plan to deploy your services.

We also strongly suggest installing the Helidon CLI (command line interface) which helps in generating and building Helidon projects.

In case you need to upgrade the version of Helidon, follow the Migration Guides.

For migration from Helidon 1.x to 2.x:

• Helidon SE 2x Migration Guide

• Helidon MP 2x Migration Guide

For migration from Helidon 2.x to 3.x:

• Helidon SE 3x Migration Guide

• Helidon MP 3x Migration Guide

Choose a Helidon flavor to explore and start using it. Check out the following:

• Helidon SE Documentation

• Helidon MP Documentation

The book Beginning Helidon is highly recommended for all Helidon 3.x users. Our colleagues Dmitry Kornilov, Daniel Kec, and Dmitry Aleksandrov authored it, while Tomas Langer and David Kral provided their reviews.

This publication serves as a comprehensive manual for designing cloud-native microservices with Helidon. It offers a detailed exploration of how to maximize the advantages of the cloud by optimizing applications for swift startup times, minimal memory consumption, and a compact disk footprint, all attainable through Helidon. By utilizing Java 17, this framework provides access to cutting-edge code features while adhering to contemporary enterprise Java standards, such as those outlined by MicroProfile.

Throughout the book, you will gain insights into enhancing your microservices with observability and security, seamlessly working with databases, and interacting with other services. The content thoroughly covers the MicroProfile 5.0 platform specifications alongside independent specifications like Messaging and Long Running Actions.

Furthermore, the book delves into how Helidon facilitates the creation of lightning-fast native executables through GraalVM integration and explains how to craft exceptionally responsive microservices using Helidon Reactive APIs.

Each chapter adopts a practical, hands-on approach, introducing various Helidon concepts through real-world scenarios and practical examples.

Beyond its instructional value, this book serves as an excellent study guide for the Oracle Helidon certification.

Available from Amazon and all other bookstores.