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Automatically generate a microservice as a self-contained standard Java component! No middleware needed! 12x faster & 92% cost savings


Microservices Java Automation Best Practices

Posted by OpenLegacy on July 21, 2020
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Java is an excellent programming language to use when transitioning from a monolithic application to a microservice architecture. Some of the giants in the online business environment — like Netflix, Google, and Amazon — rely on Java microservices to handle enormous amounts of traffic and reliably deliver outstanding digital services to their users.

The main idea behind microservices is to simplify development, integrate new technologies with your existing legacy systems faster, easier, and with fewer risks, enable efficient scaling, and improve the speed at which you deliver digital services.

OpenLegacyThe thing with monoliths is that, although they may start as fairly simple, as various teams keep working on the monolith for years, often under pressure, with unclear requirements, and without standardization — you end up with a large code amalgamation that’s difficult to deploy.

This begs the question of how you can prevent the monolith from getting any larger and, consequently, more complex. This is where Java microservices come in. They enable you to connect to the monolith and pull data and business logic from it to add new features and capabilities to your application with ease. You can create, test, and deploy microservices independently to scale your application quickly and efficiently and deliver digital services in hours instead of weeks.

What are Java microservices?

Microservices are essentially small, independent pieces of code that execute a specific business function. Each microservice has its own data store and application logic and can expose a specific API.

Thanks to their independence, microservices aren’t bound by the existing application infrastructure. This means that you can write microservices in any programming language, leverage them to embrace new technologies and innovations, and deploy them across any environment, without worrying about breaking your application.

In other words, Java microservices aren’t a special sub-type of microservices. The fact of the matter is that microservices are language-agnostic, and they function the same regardless of what programming language they’re written in.

The main reasons why microservices are often associated with Java are:

  1. Java is one of the most popular programming languages in general
  2. Java is an object-oriented (OO) language, making it popular for building systems and reusing assets
  3. It provides various libraries that make it fairly easy to use
  4. Many of the popular microservice frameworks, like Spring Boot, use Java
  5. Java has static type checking, which increases the security of your program
  6. The language is still evolving, and new features are introduced regularly
  7. There is a complete set of tools, like JUnit, that support building in Java

Want to fast-track your organization’s digital transformation? Download our free eBook — Accelerating the Digital Journey from Legacy Systems to Modern Microservices” — to see how microservices can help you leverage digital innovations 10x faster.

Main reasons to adopt microservices

Microservices are growing increasingly popular among developers and organizations looking to facilitate their digital transformation.

From the developers’ perspective, microservices are way easier to develop and deploy, compared to introducing new capabilities or features into a monolithic application. Developers can focus on a single microservices and choose the best tool for the job, depending on the microservice’s functionality. The beauty of microservices lies in the fact that they connect directly to the legacy system and handle all of the translation, making the developers’ job a whole lot easier.

Thanks to the fact that microservices are self-contained, developers don’t have to worry about how these new services will impact the application as a whole. This makes testing and deployment much faster, given the fact that they don’t have to redeploy the entire application, as is the case with monoliths.

As far as organizations are concerned, microservices are the perfect solution for legacy modernization. Microservices enable organizations to leverage their legacy assets to develop outstanding digital services and scale their applications. This makes the eventual migration to a microservices architecture easier and more cost-effective and eliminates the risks associated with creating a new system from scratch.

With microservices, organizations can embrace new technologies and leverage the computing power of the cloud without making any changes to their legacy applications that perform core business functions.

What are the main benefits of microservices?

The appeal of microservices comes from the fact that they abstract the choice between keeping a legacy system in place and creating a new system from scratch that would enable organizations to embrace innovations.

With microservices, you can have the best of both worlds. The OpenLegacy integration platform pulls data directly from your legacy systems and allows you to leverage your existing assets to create modern microservices.

That’s just one of the advantages microservices offer. Let’s take a look at the main benefits of microservices, to show you just how big of an impact adopting this approach can have on your business.

The major advantages of microservices over monolithic applications are:

  • Independence
  • Flexibility
  • Security
  • Agility


The defining characteristic of microservices is their independence. Given the fact that each microservice is completely self-sufficient, they can be developed, tested, and deployed independently.

This makes the developers’ jobs a whole lot easier. When creating a microservice, they can focus solely on its functionality, without having to account for all the complex interdependencies within a monolithic application.

Due to their self-contained nature, microservices can be independently deployed across any environment, whereas an entire monolithic application would need to be redeployed whenever developers are introducing an update or a new feature. Put simply, microservices significantly reduces your organization’s time to market.

The fact that microservices all have their data stores and application logic also means that several developer teams can work on different microservices simultaneously. This allows your organization to be more agile and roll out new features and updates in one-tenth of the time it would take to do so with monolithic applications.


The fact that microservices are isolated from one another allows the developers to bypass the constraints of monolithic legacy applications. Within a legacy application, developers have to stick to the same technology.

With microservices, you’re not locked into one technological stack and can always choose the programming language, tools, and platform that best fit the particular microservice, based on its intended functionality.

Polyglot programming increases efficiency and speeds up deployment since developers can create APIs and write application logic in whatever language best suits the situation.


Another thing that stems from the independent nature of microservices is the fact that developers can update and patch them individually. This makes it much easier for developers to debug code and perform maintenance.

Developers can also deploy security patches to individual microservices, when necessary, and focus on protecting individual features. On top of that, microservices inherently enable fault isolation — when a single microservice fails, the rest of the application remains intact.


Microservices help organizations break down large, complex projects into smaller, easier-to-manage chunks, adding the much-needed flexibility to the development process. They align perfectly with DevOps and support agile workflows.

Since microservices are completely independent, various development teams can work on different microservices concurrently. Rather than rolling out a new version of the entire monolithic application, which can take months, developers can deploy microservices and introduce new features and functionalities to the end-users daily or weekly.

This drastically reduces your time to market and enables you to build new digital services at a fraction of the cost. Microservices allow you to scale the application much more efficiently, as well as to adapt to changing requirements and prioritize developing certain features and services based on customer feedback.

What are the potential drawbacks of microservices?

Although microservices offer various benefits and are, in our opinion, the best way to modernize your legacy system, there are a few things to consider before embracing microservices.

Key considerations when adopting microservices include:

  • A shift in development culture
  • Added complexity
  • Automation and DevOps

A shift in development culture

Transitioning to microservices typically involves a shift in your organization’s team structure and a change of your business’ dynamics. Switching from linear, waterfall-based project management to an agile approach microservices call for may take a bit of time and some getting used to.

Microservices require you to build cross-functioning teams, and you need to make sure that everyone in the company is on board with the idea and comfortable with working in a different environment than what they’re used to.

Added complexity

Although it might seem counter-intuitive, given the fact that microservices aim to simplify applications and facilitate development, they can add a layer of complexity. This is mainly due to the fact that different languages and technologies are used to develop microservices, and they can utilize different monitoring tools and logging frameworks.

Whereas microservices are easy to understand and manage individually, the technological diversity between and the variety of interconnected components within an application can make it complex and difficult to manage.

Automation and DevOps

Developer terms that create and deploy microservices should look to automate the entire process. If you plan on creating a large number of microservices, deploying them manually would be tedious and time-consuming.

To effectively leverage microservices, you will need to adopt and utilize DevOps tools, such as CI/CD (Continuous Integration/Continuous Delivery), tracing, monitoring, distributed logging, etc.

This is why OpenLegacy is the perfect solution if you want to embrace microservices. Our integration platform automates microservice and API creation, allowing you to build digital services from your legacy systems in a faster, easier, more cost-effective way.

Microservices frameworks for Java

Java offers a variety of frameworks that developers can use to build microservice-based applications. We’ll go through a few of the most popular ones, to give you a better idea of what you will have at your disposal if you decide to embrace Java microservices.

Spring Boot

Spring Boot is the most popular framework for building cloud-native applications based on microservices, according to the 2019 report by Jakarta EE. More than half of Java developers around the world use this framework to build and deploy microservices.

Given the fact that it’s a market leader, Spring Boot is an excellent choice for developers who are relatively new to microservices. The framework is open-source and rich with useful features and is accompanied by excellent documentation, allowing developers to quickly learn how to make the most of Spring Boot.

Spring Boot comes with a myriad of built-in tools that address most of the common needs, but it also incorporates advanced features that provide the flexibility to handle more complex projects.

Another great thing about this framework is the fact that it comes with pre-built templates you can leverage to get started in minutes. You can start building microservices in Spring Boot with minimum configuration, but advanced configuration options are available, in case you find them necessary.

Thanks to its popularity and widespread use, there are tons of resources available online that will help your developers get started with Spring Boot. And if you intend to hire new developers, you won’t have any trouble finding the ones that have previous experience with this framework.

Eclipse MicroProfile

MicroProfile is Eclipse’s framework that was designed to help developers by defining standard APIs for building microservices in JavaEE. The idea behind MicroProfile was to create a Java Enterprise network that brings various vendor solutions together in a standardized ecosystem.

Eclipse MicroProfile was built from core JavaEE technologies like:

  • JAX-RS 2.0
  • CDI 1.2
  • JSON-P

On top of this, MicroProfile includes a set of specifications that facilitate the development of cloud-ready microservices:

  • Configuration management
  • OpenAPI
  • OpenTracing
  • JWT Authorization
  • Type-safe REST Client
  • Fault Tolerance
  • Health Checks


Dropwizard is another excellent open-source framework that’s primarily used to quickly develop RESTful web services. This framework is also a decent choice for building microservice-based applications, due to the fact that it integrates commonly used Java libraries into a comprehensive platform.

Dropwizard is an opinionated platform, much like Spring Boot, but it is a little more prescriptive. What we mean by this is that various components are integral parts of the framework, and you cannot change them easily. By default, Dropwizard uses:

  • Servlet container (Jetty)
  • REST library (Jersey)
  • Serialization and deserialization (Jackson)

This framework is a good choice if you intend to write REST-based web applications and microservices and want to get your project off the ground as fast as possible. Rapid deployment is the main advantage of Dropwizard, but keep in mind that you are sacrificing flexibility for speed.

Java microservices deployment

Another thing to consider before making the final decision to switch to microservices is the deployment method. One of the major concerns developers have when exposing the services in the monolith as microservices is finding the right tool — one that would fit the needs of their application, while also offering stability in the long-run.

Here are a few of the most popular microservices development tools that we recommend:

  1. Docker — Many developers prefer Docker for microservice deployment. Docker relies on containers to facilitate deployment. It even allows developers to break down microservices into processes running in separate Docker containers. You can also specify the deployment environment, which makes it easier to couple microservices into a larger application.
  2. Kubernetes  — Kubernetes is a portable, open-source system that can be used alongside Docker to automate the deployment and facilitate the management of microservices. The great thing about Kubernetes is that it dynamically allocates computing resources, thus improving utilization and reducing the costs.
  3. Micronaut — Micronaut is a modern, JVM-based framework that is primarily used for building modular microservices and serverless applications. It integrates cloud technologies and microservice patterns like distributed tracing and service discovery into the framework.
  4. Prometheus — Prometheus is an open-source monitoring system that enables easy microservice monitoring and facilitates microservice deployment in multi-container environments.

All of the four tools above are good in their own right, and which one you choose should largely depend on the needs of your project.

Embrace microservices today and fast-track your organization’s digital transformation

Embracing microservices is often the best option for organizations that want to modernize their legacy systems and embrace innovations, without having to take the risky, costly, time-consuming approach of creating a new system from scratch. Microservices enable you to leverage your existing legacy assets to deliver modern digital services lightning-fast.

That said, building a microservice architecture is often more difficult than most organizations anticipate. You need to identify and understand all the complicated inter-relations between various elements in a monolithic application in order to create a microservice architecture with the same functionality. You might even have to hire legacy system experts to help you navigate the complex application infrastructure.

OpenLegacy simplifies the microservice creation process greatly. Our integration platform pulls data and business logic directly from your legacy databases, mainframes, and midrange systems, and exposes it into microservices, without making any changes to the monolith.

This way, you’ll have all the external interfaces “ready to go” when building a microservice architecture, and you can do so in a phased manner. This approach also allows you to bypass the layers of complexity of the existing architecture, and automates microservice and API creation.

Thanks to our pre-built legacy connectors and the variety of options within OpenLegacy, a single Java developer can create multiple microservices a week with our platform.

Are you wondering just how big of an impact transitioning to microservices would have on your business? Click here to read our detailed case studies and see how OpenLegacy can help you transform your business and embrace digital innovations.


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