Transforming Legacy
Java-based Enterprise Applications:
10 Frameworks to Know

10 frameworks designed for agile transformation
& tips on how to avoid over-scaling & over-updating large,
legacy enterprise applications
Monika Stando
Monika Stando
Marketing & Growth Lead
June 13
14 min
Table of Contents

What are the top 10 frameworks to consider when transforming enterprise legacy applications built on Java?

When transforming enterprise legacy applications built on Java, there are several modern frameworks to consider that can improve performance, scalability, and maintainability. Here are the top 10 frameworks to consider for this purpose:

  1. Spring Boot
  2. Vaadin
  3. Quarkus
  4. Micronaut
  5. Vert.x
  6. Apache Camel
  7. Hibernate
  8. JHipster
  9. Play Framework
  10. Jakarta EE (formerly Java EE)

Let’s zoom in on the details!

#1. Spring Boot

A widely-used, versatile Java framework that simplifies creating stand-alone, production-grade Spring-based applications. It provides pre-configured templates and integrations that streamline development while offering extensive customization options.

Spring Boot’s strengths lie in its ability to reduce the amount of setup and configuration required when developing Java applications, while providing a range of features that improve development time, reduce errors, and enhance maintainability. Its flexibility and compatibility with a range of deployment environments make it a popular choice for developers looking to build modern, scalable, and efficient applications.

#2. Vaadin

A Java web application framework focused on providing a rich user interface experience through its extensive library of UI components. It enables building responsive, single-page web applications with minimal overhead.

Vaadin is specifically designed for building enterprise applications, making it ideal for creating complex applications for businesses. It provides support for security features, internationalization, and accessibility, making it easier to develop applications that meet enterprise requirements. Explore why the Insurance industry favors Vaadin.

Vaadin’s strengths lie in its powerful UI components, server-side architecture, and ability to integrate with other Java frameworks. It is a great choice for developers looking to build enterprise applications with complex user interfaces, and it enables fast development times while still providing a customizable and flexible development experience.

See the case study:
Modernizing Insurance Application
with Vaadin

#3. Quarkus

A Kubernetes-native Java stack tailored for GraalVM and OpenJDK HotSpot, designed to optimize Java applications for containers and enable effective scaling in cloud environments. It offers a streamlined development experience, fast startup times, and low memory consumption.

Quarkus is an excellent choice for building microservices and serverless applications that are optimized for the cloud. Its fast startup times, low memory footprint, and support for reactive programming make it an attractive option when developing applications that need to be highly scalable and responsive. Its straightforward API and easy-to-use tools make it accessible to developers of all levels of experience.

#4. Micronaut

A modern Java framework designed for building microservices and serverless applications with minimal overhead and maximum performance. It offers features such as dependency injection, aspect-oriented programming, and support for reactive programming.

Micronaut is an excellent choice for building modular, easily testable, and highly performant microservices and serverless applications that are optimized for the cloud. Its fast startup times, low memory footprint, and support for reactive programming make it an attractive option when developing applications that need to be highly scalable and responsive. Its lightweight and efficient dependency injection system and simple API make it accessible to developers of all levels of experience.

#5. Vert.x

A lightweight, high-performance, event-driven Java framework that enables the development of reactive, non-blocking applications. It supports various programming languages, including Java, and is well-suited for building scalable, distributed systems.

Vert.x’s strengths lie in its high performance, asynchronous programming model, polyglot support, modular architecture, reactive programming, scalability, and easy integration with other systems. It is an excellent choice for building responsive and scalable applications that need to handle a large number of concurrent connections and requests. Its versatile nature makes it an attractive option for developers of all levels of experience and with different language preferences.

#6. Apache Camel

An integration framework that allows you to define routing and mediation rules between different systems and services. With its rich set of connectors and components, Apache Camel simplifies integration tasks for enterprise applications.

Apache Camel’s strengths lie in its ability to simplify the integration of different systems and technologies, its support for multiple protocols, its flexible routing and transformation capabilities, its easy-to-learn API, its modular architecture, its large community support, and its extensibility. It is an excellent choice for developers looking to integrate different systems with flexible and powerful transformation capabilities.

#7. Hibernate

A popular Java-based Object-Relational Mapping (ORM) framework that facilitates mapping Java objects to relational database tables. Hibernate can help modernize legacy applications by streamlining database access and improving data management.

Hibernate’s strengths lie in its ability to simplify database access, its cross-platform compatibility, its object-relational mapping capabilities, its performance optimization features, its database independence, its easy-to-learn API, and its large community support. It is an excellent choice for developers looking to simplify their database access and work with object-oriented programming constructs when interacting with relational databases.

#8. JHipster

A development platform that simplifies generating, developing, and deploying Spring Boot + Angular/React/Vue web applications and Spring microservices. JHipster can help accelerate the modernization process by providing a robust, pre-configured application template.

JHipster allows developers to quickly create applications using a wide range of pre-configured tools and technologies, including Spring Boot, Angular, and React. This reduces the amount of boilerplate code that needs to be written and speeds up the development process.

JHipster’s strengths lie in its ability to simplify and accelerate the development process, its flexible architecture, its support for multiple programming languages, its easy deployment capabilities, its focus on security, its tools for promoting code quality and consistency, and its large community support. It is an excellent choice for developers looking to quickly build modern web applications using popular technologies.

#9. Play Framework

A reactive web application framework for Java and Scala that promotes a non-blocking, asynchronous programming model. Play Framework is well-suited for modernizing legacy applications that require high concurrency and low latency.

Play Framework is built on top of Akka, which provides a high-performance network layer. This makes it ideal for developing fast and responsive applications that require low latency and high throughput.

Play Framework uses an event-driven, non-blocking programming model, which enables developers to build highly responsive and scalable applications that can handle a large number of simultaneous connections.

Play Framework excels in high performance, asynchronous programming, modular architecture, effortless usage, support for multiple programming languages, built-in testing, and extensive community backing. It’s an ideal selection for developers seeking to create swift, adaptable, and up-to-date Java or Scala-based web applications.

#10. Jakarta EE (formerly Java EE)

A set of specifications and APIs for developing and running enterprise applications in the Java programming language. Jakarta EE provides a wide range of features, such as web services, persistence, security, and messaging, which can help modernize and enhance legacy Java applications.

Jakarta EE provides an extensive set of APIs that cover a wide range of enterprise application development needs, including web services, security, messaging, and more. This makes it easy for developers to build complex enterprise applications without having to write low-level code.

Jakarta EE is platform-independent, meaning that applications developed using Jakarta EE can be run on different operating systems and hardware platforms without the need for significant modifications.

Jakarta EE’s strengths lie in its extensive set of APIs, platform independence, scalability, security features, support for multiple programming languages, large community support, and easy integration with other systems.

Each of these frameworks offers unique features and advantages, and the best choice depends on your specific requirements, such as performance, scalability, user experience, and cloud readiness. Evaluate each framework based on your application’s needs and goals to determine the most suitable option for transforming your enterprise legacy Java application.

How to modernize enterprise legacy applications written in Java?

Modernizing enterprise legacy applications written in Java involves a combination of updating technology stacks, refactoring code, adopting modern architectures, and improving development processes.

Assess the current state

Start by analyzing the existing application to identify its strengths, weaknesses, and potential areas for improvement. This includes evaluating the application’s architecture, code quality, performance, security, and user experience.

Define modernization goals

Set clear objectives for the modernization process, such as improving performance, enhancing user experience, increasing maintainability, or migrating to the cloud.

Plan the modernization process

Develop a detailed plan outlining the steps, resources, and timelines required to achieve your modernization goals. Consider dividing the process into manageable phases to minimize disruptions and risks.

Update technology stack

Replace outdated libraries, frameworks, and tools with more modern alternatives that offer better performance, security, and support. Consider migrating to a modern Java framework like Spring Boot, Micronaut, or Quarkus to streamline development and take advantage of newer features and best practices.

Refactor code

Gradually refactor the existing codebase to improve its quality, maintainability, and performance. Focus on areas with the most significant impact, such as performance bottlenecks, duplicated code, or poor design patterns.

Consider adopting a microservices architecture

Break down the monolithic legacy application into smaller, more manageable services that can be developed, deployed, and scaled independently. This approach enables better resource utilization, easier maintenance, and increased flexibility when adding new features or making changes to existing ones.

Improve user experience

Modernize the user interface by adopting responsive web design, single-page application (SPA) architecture, and leveraging modern UI frameworks like Vaadin or Angular. This will help provide a better user experience on various devices and platforms.

Containerization and cloud migration

Containerize your legacy Java application using technologies like Docker and Kubernetes, which enable more efficient deployment, scaling, and management of your application. Migrate your application to the cloud to leverage the benefits of cloud-based infrastructure, such as auto-scaling, cost optimization, and improved availability.

Implement DevOps practices

Adopt DevOps practices, such as continuous integration and continuous deployment (CI/CD), automated testing, and infrastructure-as-code, to streamline development processes, reduce errors, and ensure faster delivery of new features and improvements.

Enhance security and compliance

Update your application’s security practices to meet modern standards, such as implementing secure coding practices, addressing known vulnerabilities, and ensuring compliance with relevant regulations and industry best practices.

Monitor and optimize

Implement robust monitoring and observability solutions to gain insights into your application’s performance, resource usage, and potential issues. Continuously optimize and improve the application based on these insights to ensure its ongoing success.

By following these steps, you can gradually modernize your Java-based enterprise legacy applications while minimizing risks, costs, and disruptions to your existing workflows and processes.

What are the challenges when it comes to scaling large enterprise applications?

Scaling large enterprise applications can be challenging due to the increased complexity and demands associated with managing a growing user base, data volume, and infrastructure. Some of the common challenges associated with scaling large enterprise applications include:

Performance bottlenecks

As the number of users and data volume increases, performance bottlenecks can arise in various parts of the application, such as slow database queries, inefficient algorithms, or resource-intensive operations. Identifying and resolving these bottlenecks is crucial for maintaining optimal application performance.

Data management

Large enterprise applications often deal with vast amounts of data, which can make data storage, retrieval, and processing more complex and resource-intensive. Implementing effective data management strategies, such as caching, data partitioning, or sharding, is essential for ensuring efficient data handling and scalability.

Infrastructure management

Scaling enterprise applications requires managing and provisioning the necessary infrastructure resources, such as servers, storage, and networking components. This can be complex and time-consuming, especially when dealing with on-premises or hybrid environments.

Application architecture

Monolithic application architectures can hinder scalability, as they require the entire application to be scaled together. Adopting more scalable architectures, such as microservices or serverless computing, can help alleviate this issue but may require significant refactoring of the existing application.

Load balancing and distribution

Effectively distributing and balancing the workload across multiple instances or components of the application is critical for achieving scalability. Implementing load balancing strategies and techniques, such as horizontal scaling, can help prevent single points of failure and ensure application responsiveness under high load.

Security and compliance

Scaling large enterprise applications often involves addressing new security vulnerabilities and adhering to stricter compliance requirements. Ensuring that the application remains secure and compliant while scaling can be challenging, particularly when dealing with sensitive data or regulated industries.

Monitoring and observability

As enterprise applications grow, it becomes increasingly important to monitor their performance, resource usage, and error rates. Implementing effective monitoring and observability solutions can help identify and resolve issues quickly, but it can be challenging to manage and analyze the vast amount of data generated by large-scale applications.

Development and deployment processes

Scaling large enterprise applications often requires streamlining development and deployment processes to accommodate the increased complexity and demands. Implementing continuous integration and continuous deployment (CI/CD) pipelines, automated testing, and infrastructure-as-code can help improve efficiency but may require significant changes to existing workflows and practices.

Cost management

As applications scale, infrastructure and operational costs can increase significantly. Managing and optimizing these costs, while still meeting performance and availability requirements, can be a challenge for many organizations.

Team coordination and communication

Scaling large enterprise applications often involves coordinating and communicating across multiple teams, such as development, operations, and security. Ensuring effective collaboration and communication as the application grows can be a challenge, particularly in distributed or large organizations.

Addressing these challenges requires a combination of careful planning, adopting scalable architectures and technologies, implementing effective development and deployment processes, and investing in monitoring and observability solutions to ensure the successful scaling of large enterprise applications.

How to avoid being pressured into over-scaling and updating large, legacy enterprise applications?

To avoid overdoing the scaling and modernization of large legacy enterprise applications, it is essential to adopt a balanced and strategic approach. Here are some tips to help you achieve this:

#1. Establish clear objectives

Clearly define the goals and objectives of your scaling and modernization efforts. Focus on addressing specific pain points, such as performance bottlenecks, security vulnerabilities, or maintainability issues, rather than attempting to modernize every aspect of the application.

#2. Prioritize critical components

Identify the most critical components of the application that have the greatest impact on performance, scalability, and maintainability. Focus on modernizing these components first, rather than trying to tackle the entire application at once. This is where the Agile Delivery Lead comes to the rescue to help prioritize tasks. Learn more about the role of the ADL.

#3. Embrace incremental changes

Instead of undertaking a massive overhaul, adopt an incremental approach to modernization. Implement small, manageable changes over time, and continuously monitor their impact on the application’s performance and maintainability.

#4. Leverage existing investments

Rather than replacing all existing technologies and infrastructure, look for ways to leverage and extend your current investments. For example, consider integrating new microservices with existing components, or using APIs to expose legacy functionality to modern front-end applications.

#5. Perform cost-benefit analysis

Before embarking on any modernization effort, conduct a thorough cost-benefit analysis to ensure that the expected benefits outweigh the costs and risks involved. This will help you avoid unnecessary expenses and focus on initiatives that provide the greatest return on investment.

#6. Avoid “silver bullet” solutions

Be wary of adopting new technologies or approaches just because they are trendy or perceived as a “silver bullet.” Instead, carefully evaluate each potential solution based on its suitability for your specific needs and constraints.

#7. Involve stakeholders

Engage key stakeholders, including business users, IT staff, and management, in the modernization process. Their input and feedback can help ensure that your modernization efforts align with business priorities and do not disrupt existing workflows.

#8. Monitor and measure progress

Continuously monitor the performance and maintainability of your application as you modernize it. Establish key performance indicators (KPIs) to measure the success of your modernization efforts, and adjust your strategy as needed based on the results.

By adopting a balanced, strategic approach to scaling and modernizing large legacy enterprise applications, you can ensure that your efforts are focused, cost-effective, and aligned with your organization’s goals. This will help you avoid overdoing it and ensure that your modernization efforts deliver maximum value.

Wrapping things up: Modernizing enterprise legacy applications written in Java

There are a few modern frameworks to consider when transforming legacy Java-based enterprise applications: Spring Boot, Vaadin, Quarkus, Micronaut, Vert.x, Apache Camel, Hibernate, JHipster, Play Framework, and Jakarta EE.

Each framework has unique strengths and advantages, and the best choice depends on specific requirements such as performance, scalability, user experience, and cloud-readiness.

Scaling large enterprise applications can pose several challenges that require careful planning and adoption of scalable architectures, technologies, and deployment processes. Key challenges include performance bottlenecks, data management, infrastructure management, application architecture, load balancing, security and compliance, monitoring, cost management, and team coordination.

To avoid overdoing the scaling and modernization of large legacy enterprise applications, a balanced and strategic approach is recommended. This involves establishing clear objectives, prioritizing critical components, embracing incremental changes, leveraging existing investments, performing a cost-benefit analysis, avoiding “silver bullet” solutions, involving stakeholders, and monitoring and measuring progress.

Modernizing enterprise legacy applications is complex, hence don’t hesitate to get in touch to consult your strategy. We are here to share our experience and best practices. Get in touch!

Monika Stando
Monika Stando
Marketing & Growth Lead
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