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The fundamentals of Micronaut and microservices development

The Micronaut framework offers developers an efficient way to build distributed applications, particularly thanks to quick startup capabilities, a multipurpose CLI and more.

Designed to enhance Java-based web application development, the Micronaut framework enables developers to create modular, easily testable microservices applications while producing small and fast executables. It preserves the model-view-controller pattern and other familiar frameworks, but its designed to meet the needs of microservices and cloud-centric programming.

Micronaut's capabilities are particularly important for microservices with a low memory footprint, as well as applications and functions that benefit from small, lightweight deployments and regularly rely on cold starts. Micronaut contains additional aspects that fuel its potential as a substantial, yet flexible framework, especially for cloud-based and serverless applications.

Micronaut and microservices

Micronaut incorporates all of the existing and established microservices patterns that developers rely on, eliminating the need to piece together separate tools and frameworks. For example, Micronaut includes native support for service discovery, distributed configuration, client-side load balancing and authentication.

The framework works with Java, Kotlin and Apache Groovy development programming languages, and it can use both Apache Maven and Gradle as build tools. Moreover, developers can access various data stores in both blocking and nonblocking ways, connect services via REST HTTP calls or asynchronously through a message broker and secure a system with JSON web tokens.

Business standards require fast interactions between numerous independent applications performing highly specific tasks. These small, service-oriented applications work together as microservices to enable high efficiency. However, microservices generally require running different processes at startup.

For example, one such process includes executing numerous integration tests, which increases startup time. Moreover, deployments that use Spring Boot require time to load Spring's ApplicationContext and WebApplicationContext. Finally, you must read the bytecode of every Spring bean object individually, which is a time-consuming process.

The Spring and Grails frameworks use reflection-based inversion of control to load and cache data for every field, method and constructor. By contrast, Micronaut doesn't depend on the size of the code base. It performs these tests at compile time to enable fast startups. Moreover, the test suite setup in Micronaut is minimal, saving even more time.

Less memory consumption

Micronaut achieves low overhead through a built-in compile-time dependency injection and aspect-oriented programming model that helps alleviate excessive startup times and reduces the memory consumption that can hinder application response. Moreover, minimal modifications of the abstract syntax tree, processing annotations and proxying all occur at application startup.

In an era of increased reliance on containers, container management systems and serverless computing, you should not underestimate the importance of low-memory microservices and applications that have minimal overhead during cold starts. Micronaut demonstrates a notable improvement in memory usage through reduced use of runtime reflection. Where Spring Boot might require hundreds of megabytes per microservice, Micronaut requires significantly less. And for those organizations that rely on many diverse microservices, lower memory consumption can translate into significant operational savings.

Cloud-native features

Cloud-native programming is common in enterprise software development, as organizations choose to deploy applications to platforms that abstract server and storage details. Instead of managing servers and data centers, businesses provide instantly scalable services that they can redeploy and monitor on cloud resources with the help of sophisticated tooling and automated processes.

Micronaut also enables serverless computing with AWS Lambda. Built on top of the Java networking library Netty, Micronaut ensures support for asynchronous programming and the Reactive Streams initiative. The framework includes its own nonblocking web server and built-in profiles. These stripped-down, yet functional applications can work as building blocks of web or command-line applications.

A multipurpose CLI

Developers can use the Micronaut command-line interface (CLI) to create new projects. The CLI offers a powerful tool to create functions, command-line apps, services and profiles. In fact, the concept Micronaut's CLI follows for application creation is comparable to the CLI on Grails.

The CLI includes commands to generate specific categories of projects, which provides developers a varied choice of build tools, test frameworks and languages. Developers can also use the CLI tool to create beans, clients and controllers. They can also use the tool to modify existing projects. The Micronaut CLI supports both Gradle and Maven builds and provides useful code generation commands for things like client interfaces.

Since the creator of Grails also developed Micronaut, the new framework draws on lessons learned over time building real-world applications in Spring, Spring Boot and Grails. It aims to improve development efficiency over other frameworks. Moreover, it recognizes the relationship between modern applications and cloud computing technologies. Built from the bottom up, Micronaut always keeps the cloud in mind instead of just adding packages.

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