In the world of modern Java microservices, developers are faced with a variety of frameworks and tools to choose from. Two popular options in this space are Quarkus and Micronaut. Both of these frameworks offer unique features and advantages, making the choice between them a significant decision for developers. In this article, we’ll delve into the key differences and similarities between Quarkus and Micronaut to help you make an informed choice.
Core Philosophies
Quarkus: Quarkus is heavily reliant on Jakarta EE / Java EE and Eclipse MicroProfile APIs. It’s designed to be compatible with existing Java EE applications and is built on an extension architecture, which allows for easy integration of third-party frameworks. Notably, Quarkus enables the use of Spring DI, Web, and Data JPA annotations within your applications.
Micronaut: Micronaut takes a different approach by defining its own APIs. It draws inspiration from frameworks like Spring and Grails. Micronaut provides an Aspect-Oriented Programming (AOP) implementation that doesn’t rely on reflection to define cross-cutting concerns, such as logging.
On-Line initializers
Quarkus: You can bootstrap a Quarkus application using many tools. The online application initializer is available here: https://code.quarkus.io/ . From there, you can select the Maven GAV, the Java version and the libraries to add which in Quarkus are named extensions.
Micronaut. The online application initializer is available here: https://micronaut.io/launch :
From there, you can also select the Maven coordinates, the Build tool and the Test Framework. Then, choose the libraries to add which in Micronaut are called “Features“.
Hello World: Quarkus vs Micronaut
Here is a minimal example of REST Service using both frameworks.
This is a Quarkus Hello World REST Service which uses, as you can see, plain Jakarta EE API:
package org.acme;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;
@Path("/hello")
public class GreetingResource {
@GET
@Produces(MediaType.TEXT_PLAIN)
public String hello() {
return "Hello from RESTEasy Reactive";
}
}
This is the equivalent Micronaut Hello World REST Endpoint:
package example.micronaut;
import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;
import io.micronaut.http.annotation.Produces;
@Controller("/hello")
public class HelloController {
@Get
@Produces(MediaType.TEXT_PLAIN)
public String index() {
return "Hello World";
}
}
As you can see, Micronaut uses its own packages (Features) to compile and run its Applications.
Testing applications
Testing is a core part of every framework and both Quarkus and Micronaut provide substantial support for Testing application on top of the standard JUnit Jupiter framework.
Quarkus Test application typically use the @QuarkusTest abstraction which sits on top of JUnit. Also, a Quarkus Test for a REST Endpoint generally leverages RestAssured library:
package org.acme;
import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;
import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.is;
@QuarkusTest
public class GreetingResourceTest {
@Test
public void testHelloEndpoint() {
given()
.when().get("/hello")
.then()
.statusCode(200)
.body(is("Hello from RESTEasy Reactive"));
}
}
It is important to note that Quarkus provides support for the automatic provisioning of services in development and test mode. This capability is called Dev Services. To learn more about Quarkus testing refer to: How to Test Quarkus applications
Micronaut applications also have an abstraction, @MicronautTest, which sits on top of JUnit 5 Jupiter to provide support for Micronaut Tests:
import static org.junit.jupiter.api.Assertions.*;
import io.micronaut.http.HttpRequest;
import io.micronaut.http.MediaType;
import io.micronaut.http.client.HttpClient;
import io.micronaut.http.client.annotation.Client;
import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
import org.junit.jupiter.api.Test;
import jakarta.inject.Inject;
@MicronautTest
public class HelloControllerTest {
@Inject
@Client("/")
HttpClient client;
@Test
public void testHello() {
HttpRequest<?> request = HttpRequest.GET("/hello").accept(MediaType.TEXT_PLAIN);
String body = client.toBlocking().retrieve(request);
assertNotNull(body);
assertEquals("Hello World", body);
}
}
Developer Console
Quarkus: when running in Dev Mode, it provides a Dev UI that allows to view extension status, apply changes in the configuration, manage Continuous Testing ,check the status of the Dev Services and more.
Micronaut: provides a Control Panel web UI that allows you to view and manage the state of your Micronaut application, typically in a development environment. You can further extend the default Control panel with custom Views and AbstractControlPanel implementations.
Dependency Injection and Inversion of Control
Quarkus: Quarkus implements a subset of the Contexts and Dependency Injection (CDI) specification, supporting DI features. However, it does have certain limitations in terms of CDI features.
Micronaut: Micronaut offers a simpler compile-time dependency injection implementation. It avoids reflection wherever possible and minimizes the use of proxies. This approach can lead to better performance and resource utilization.
Data Access
Micronaut uses Micronaut Data, a database access toolkit that leverages Ahead of Time (AoT) compilation to precompute queries for repository interfaces, enhancing database interaction. It draws inspiration from GORM and Spring Data but offers several improvements such as:
- No runtime model: Unlike GORM and Spring Data, Micronaut Data doesn’t maintain a memory-consuming runtime meta-model, resulting in efficient memory usage.
- No query translation: Micronaut Data eliminates runtime translation, as query generation is handled at compile time by the Micronaut compiler.
- No reflection or runtime proxies: By avoiding reflection and runtime proxies, Micronaut Data delivers improved performance, smaller stack traces, and reduced memory consumption.
- Type safety: Micronaut Data enforces compile-time checks on repository method implementations for added reliability.
// BookRepository is a data repository
// By extending CrudRepository you enable automatic generation of CRUD (Create, Read, Update, Delete) operations.
@Repository
interface BookRepository extends CrudRepository<Book, Long> {
Book find(String title);
}
Quarkus, on the other hand, relies on the popular Hibernate framework to manage persistence of Java Objects on the Database. Besides, Quarkus can leverage Panache which is a powerful and convenient extension that simplifies data access and manipulation in Java applications. It provides a compact and type-safe way to work with databases by building on top of Hibernate ORM.
Example:
@Entity
public class Person extends PanacheEntity {
public String name;
public int age;
}
Finally, Quarkus has support for no-SQL databases, such as MongoDB, as separate extensions. To learn more check this article: Getting started with MongoDB and Quarkus
Reactive and Declarative Programming
Both Quarkus and Micronaut are compatible with reactive programming, but they have differences in their approach:
Quarkus: Quarkus supports reactive programming using Netty and Vert.x as reactive engines. It offers support for Reactive Messaging with Apache Kafka and AMQP. Reactive clients for MySQL, PostgreSQL, and MongoDB are also available. Quarkus provides an alternative declarative way to implement HTTP endpoints with Reactive routes.
Micronaut: Micronaut includes non-blocking HTTP server and client APIs based on Netty. It also supports Reactive MySQL and PostgreSQL clients through third-party libraries. Apache Kafka and RabbitMQ are compatible with Reactive APIs.
Resilience & Fault Tolerance
Both frameworks provide features to enhance resilience and fault tolerance:
Quarkus: Quarkus incorporates the MicroProfile Fault Tolerance specification, offering capabilities such as Retry, Timeout, Fallback, and Circuit Breaker.
Micronaut: Micronaut supports Retry, Fallback, and Circuit Breaker patterns as AOP advices.
Cloud Support
Quarkus: Quarkus primarily targets Kubernetes cloud environments and provides automated generation of Kubernetes resources. It also offers serverless support for AWS Lambda and Azure Functions.
Micronaut: Micronaut natively supports various cloud features, including distributed configuration (Consul, AWS Secrets Manager), service discovery (Consul, Eureka), and serverless functions (AWS Lambda, Azure Functions).
Language Support
Quarkus: Quarkus extends its support to Java, Kotlin, Scala, and Groovy via extensions.
Micronaut: Micronaut supports Java and Groovy out of the box and offers Kotlin support, with Scala available via a plugin.
Native execution
Both Quarkus and Micronaut support the generation of native executables using a polyglot embeddable virtual machine (GraalVM).
Compiling native executables ahead of time with GraalVM largely improves startup time and reduces the memory footprint of JVM-based applications.
Conclusion
Quarkus and Micronaut are both excellent choices for developing modern Java microservices. The decision between them should depend on your specific project requirements and your familiarity with the programming models they offer. Quarkus is well-suited for Jakarta EE and Java EE environments and provides extensive cloud support and amazing performance. Micronaut offers as well impressive performance and simplicity, with its compile-time dependency injection and AOP features. Ultimately, the choice between these two frameworks should align with your project goals and development preferences.
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