Java In The World Of Microservices

A microservice is a small, loosely coupled distributed service. Microservice Architectures evolved as a solution to the scalability and innovation challenges with Monolith architectures (Monolith applications are typically huge – more 100, 000 line of code). It allows you to take a large application and decompose or break into easily manageable small components with narrowly defined responsibilities.

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Reasons for using Microservice

• For a large application, it is difficult to understand the complexity and make code changes fast and correctly, sometimes it becomes hard to manage the code.
• Applications need extensive manual testing to ensure the impact of changes.
• For small change, the whole application needs to be built and deployed.
• The heavy application slows down start-up time.

Benefits of Microservices

• Small Modules –
  Application is broken into smaller modules which are easy for developers to code and maintain.
• Easier Process Adaption –
  By using microservices, new Technology & Process Adaption becomes easier. You can try new technologies with the newer microservices that we use.
• Independent scaling –
  Each microservice can scale independently via X-axis scaling (cloning with more CPU or memory) and Z-axis scaling (sharding), based upon their needs.
• Unaffected –
  Large applications remain largely unaffected by the failure of a single module.
• DURS –
  Each service can be independently DURS (deployed, updated, replaced, and scaled).

Restrictions of Microservices

• Configuration Management –
  As it becomes granular the headache comes for configuring the services and monitoring those. You need to maintain configurations for hundreds of components across environments.
• Debugging –
  Tracking down the service failure is painstaking job. You might need to look into multiple services across different components. Centralized Logging and Dashboards are essential to make it easy to debug problems.
• Automation – Because there are a number of smaller components instead of a monolith, you need to automate everything – Builds, Deployment, Monitoring etc.
• Testing –
  Needs a greater effort for end to end testing as it needs all the dependent services to be up and running.

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List of Microservices in JAVA

• Spring Boot

A survey indicates Spring Boot to be the leading framework for building microservices applications within Java and for a good reason, too. In general, Spring Boot is a mature, open-source, and feature-rich framework with a vast community to turn to for support. Spring Boot microservices can be easily deployed on various platforms, be it Dockers or bare metal servers. This popular Java framework comes with in-built functionalities like security autoconfiguration and starter dependencies that allow for rapid application development in Java.

Getting started with Spring Boot is as simple as visiting start.spring.io to launch an automated application template in just a few minutes. Not surprisingly, Java framework is exceptionally popular, owing to the convenience and flexibility it offers, and firms that wish to deploy Spring Boot microservices architecture can find experienced staff quite easily. For professionals, various pieces of training and certifications in Spring Boot are available to upgrade their skill set with this easy-to-use microservices framework that can be exploited even by less experienced teams to solve complex business problems. In practice the Spring framework has proved to be the most effective standard for microservice development.

• Micronaut 

Micronaut is a modern, JVM-based, full-stack microservices framework. It is designed for building easily testable microservice applications and implementing serverless functions. The best part about Micronaut is the quick startup time, which is due to non-reliance on reflection-based IoC frameworks, a considerable departure from Spring Boot. Another great feature of Micronaut is the exceptional built-in support for cloud, which makes it a breeze to work on AWS or write serverless applications.

It is a fact that Micronaut was developed based on lessons learned through the real-world applications of Spring and Spring Boot over the years. As a result, many of the APIs within the framework are inspired by Spring which makes it easier for new developers to find their feet. Micronaut framework also overcomes several of the shortcomings intrinsic to frameworks like Spring and Spring Boot, through upsides like:

• Reduced memory footprint
• Faster startup time
• Easy unit testing
• Less usage of proxies and reflections

• Ballerina

Ballerina is not a microservices framework. Instead, it is a distributed programming language which can be used to write distributed applications. This enables developers to build customised network applications from scratch by writing software using the open-source programming language.

Overall, Ballerina is a cloud-native programming language that simplifies the microservices framework further by overcoming the challenge of distributed tracing and observability. With built-in support, it is possible to enable tracking and monitoring without any additional lines of code.

As Ballerina is mainly designed for cloud computing, it also includes annotations for Docker and Kubernetes, making it possible to deploy into those environments with minimal coding. Ballerina also makes the developer aware of any potential security threats, network failures and communications while writing the program itself for seamless deployment at later stages.

• Dropwizard 

Dropwizard is an open-source framework, which is popularly known for the rapid development of RESTful web services. Dropwizard is also considered quite easy to use and works well for microservices application development. It integrates tried and tested Java libraries into a functional platform while offering templates with Java-based interfaces like FreeMarker and Mustache. Similar to Spring Boot, Dropwizard applications are packaged into fat JAR files with the Jetty application server embedded.

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According to some experts, Dropwizard lacks a little bit in terms of flexibility when compared with other frameworks like Spring Boot. However, it scores in terms of reliability by integrating a well-tested combination of tools that are pre-wired to get your project off the ground quickly. Even though Dropwizard has no built-in dependency injection solution, it does have integrations for Guice and Dagger. Overall, Dropwizard flaunts superior performance and operations amicability for microservices application advancement.

• Eclipse MicroProfile 

The Eclipse MicroProfile project is an upgrade to Java EE, aimed at optimising Enterprise Java for building Microservices architecture and cloud-native applications. The system is based on a subset of Jakarta EE WebProfile APIs, which means the process of building MicroProfile applications remains essentially the same.

MicroProfile is getting popular not only for the familiarity of usage but also for attempting a standardized API for microservices in Java by bringing together a bunch of vendors and organisations. The critical APIs in MicroProfile include CDI, JAX-RS, JSON-P, Metrics and Config.

The idea of microservices is simple yet powerful, and is fast gaining popularity to improve the end-user experience by breaking down monolithic applications into smaller bits that are lighter, faster, and programmed to run independently or cohesively, as required. Not surprisingly, several experts list microservices as an advanced skill that Java Developers must possess in 2020.

• Spark

Spark is one of the best Java microservices frameworks for creating web apps in Java 8 and Kotlin. This micro web framework allows developers to start rapidly and with minimal effort. It was inspired by Sinatra, a famous Ruby micro-framework.

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• Jersey

Jersey framework is an open-source framework for developing RESTful web services in Java. It makes it easy for the developers to build RESTful web services using Java and JVM. It offers support for JAX-RS APIs and serves as a JAX-RS Reference Implementation that simplifies the development of RESTful services.

• Swagger

Swagger helps developers in documenting APIs. It is an Interface Description Language for describing RESTful APIs expressed using JSON. It is a set of open-source software tools that allow developers to easily build, design, document, and use RESTful web services.

It is widely used by a large number of companies to deliver great APIs and streamline API development.

• Restlet

Restlet framework helps Java developers create better Java APIs with REST architecture style. It is an open-source framework and is widely used by developers for creating secure and scalable web APIs. It offers powerful routing and filtering capabilities, numerous extensions, and a unified client and server Java API. It is available for all major platforms.

As microservice is a common and widely-adopted software design pattern, it is being considered one of the top skills of software developers regardless of the technologies or frameworks they are working

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Java Microservices Example

This is an example of a Java microservice with REST API. You can create as many services as you want with REST endpoints as per your requirements and architecture.

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;
@RestController
@EnableAutoConfiguration
public class HelloWorld {
@RequestMapping(“/”)
String example() {
return “Welcome to SPEC INDIA!”;
}
public static void main(String[] args) throws Exception {
SpringApplication.run(HelloWorld.class, args);
}
}

Output:

Welcome to SPEC INDIA!

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