Cutting-edge applications are necessary to maintain a competitive edge in the post-COVID era. As users demand faster load times, seamless interfaces, and accessibility across devices, businesses must evolve their technology. However, legacy applications—often critical to business operations—can hold organizations back with outdated architectures and technology stacks. This is where app modernization plays a vital role.
App modernization bridges the gap between legacy systems and modern demands, enabling organizations to integrate new functionalities without the need to rebuild from scratch. This article explores four key strategies for successful app modernization and best practices to guide your journey.
What is application modernization, and why is it important?
Application modernization is the process of upgrading legacy applications to modern environments, including cloud infrastructure. It often involves code optimization, redesigning user interfaces, and migrating applications to new platforms, all while ensuring compatibility with modern devices, cloud services, and security protocols.
Key benefits of app modernization include:
- Innovating with AI-based enhancements, like image processing and data analytics.
- Enhancing user experiences by improving UI/UX for faster task completion.
- Mitigating security risks and removing vulnerabilities.
- Unlocking new revenue opportunities or delivering added value to existing customers.
- Leveraging cloud economies for cost-effective, scalable app architecture.
Modernization also reduces technical debt—the accumulation of outdated technologies that impede innovation. According to a Dell report, 60-80% of IT budgets are allocated to maintaining legacy applications. App modernization helps reduce these costs over time while enhancing agility and speeding up response to market changes.
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Common app modernization strategies
Here are four key strategies for app modernization:
1. Rehosting
Rehost, or lift and shift, seeks solutions that require no application source code changes. The process usually involves moving the application from an on-prem data center to the cloud. For example, you may move your application from bare metal servers to AWS EC2 cloud instances or move from self-hosted Kubernetes to Amazon EKS.
How?
Rehosting typically relies on third-party tooling for success. Major cloud providers have built-in solutions to move applications to their environments. The process varies based on source and destination technologies. It also requires significant run-time support to ensure that the application continues to run as expected.
When?
Rehosting is preferred when organizations want fast returns for minimal investment. Cost reduction and performance improvements are almost immediate. However, it is not a permanent solution to removing technical debt. It does not solve the challenges around user experience and productivity. Hence, it is typically the first, or “stop-gap”, solution, so the application keeps running for end users while it is modernized further. Engineers may also be able to reuse parts of the existing code for further optimization.
2. Refactoring
Refactoring is making source code changes without affecting external application behavior. Instead, the focus is on improving component features and structure to remove technical debt and increase cloud compatibility. For example, you may replace certain code functionality with API calls or rewrite a specific feature to remove a security vulnerability. Refactoring sometimes includes replatforming, which is changing the technology of internal components—for example, you may swap an on-prem database with a cloud database service.
How?
Refactoring requires developers to look at the existing application codebase with fresh eyes. They make the code more readable, usable, and bug-free. Changes are typically made in three broad areas:
- Source code refactoring, like fixing logic errors or increasing modularity.
- Database refactoring, like schema changes or replacing with a cloud database.
- User interface refactoring that changes the UI for consistency and enhanced usability.
When?
Refactoring is preferred when the application is functionally robust and needs specific, definable improvements. It is also useful when most of the codebase is new, and only a few legacy components require change. Sometimes, it is another preliminary step in a larger app modernization project.
3. Rearchitect
Rearchitecting makes significant design changes so the application works optimally in the new environment. The goal is to take full advantage of cloud-native features by implementing a scalable, service-oriented framework that replaces current application code. Existing code may be reused, but the code structure changes significantly—for example, building microservices for each application functionality and containerizing them to reduce dependencies.
How?
Developers initially focus on understanding the existing application’s functionality, performance requirements, and usage patterns. Next, they identify the new technologies and architectural patterns that will replace the existing ones. They may look at existing code modules, APIs, and overall design to identify areas of improvement. They make and test changes in the existing environment before moving to the new one.
When?
Rearchitecting is preferred when the goal is to migrate the application to a specific new platform, but the application is not optimally “ready” in its current state. It is also useful when the application functions well but performs poorly—for example, if it consumes too many resources or has hit maximum user capacity.
4. Rebuild
Rebuild, as the name suggests, builds the application again to take best advantage of modern technologies. You don’t replace your application with a third-party SaaS offering. Instead, you use the existing application as a requirements blueprint. You then build it again using another programming language, new coding frameworks, or a new technology stack. If certain existing components are useful, you can rebuild the application by integrating new components with existing ones.
How?
Rebuilding is a complex process of rethinking system logic configurations and business specifications. You must considerably change the system while keeping it in conformity with the old business requirements. Teams also change the application's look and feel for more modern user experiences. Rebuilding typically involves finding flexible yet customizable best-fit technologies. The goal is to align with the past while ensuring that the solution remains useful for the future.
When?
Sometimes, teams start refactoring or rearchitecting but discover more complications. Rebuilding is then preferred, since rearchitecting does not solve the challenges. It allows teams to recreate while avoiding previous technical pitfalls. Rebuilding is also preferred if you can justify the cost in the long term. It is better to rebuild once than to refactor repeatedly as new challenges come up.
Comparison of a Java Swing UI before and after migrating to Vaadin.
App modernization best practices
Before embarking on your app modernization journey, consider these best practices:
Assess your application characteristics
There are two broad categories of applications.
- Consumer-scale applications like e-commerce or social media.
- Enterprise-scale applications like CRM or health applications for hospitals.
These two types of applications have different modernization requirements. For example, consumer-scale applications require fast load times and intuitive user interfaces, while enterprise-scale applications require more reliability and accuracy. Understanding the application’s requirements drives future technical decisions and is critical for successful modernization.
Select the right team
Application modernization requires developers with a broad skill set. You want a team that specializes in both old and new technologies. For instance, you might need developers with experience in Java, JavaScript, Scala, and cloud technologies for Java app modernization. Insufficient team experience can delay the process and add to costs.
Plan for scale
It is a myth that moving to the cloud automatically makes applications more scalable. Cloud scalability typically takes the “horizontal” approach of adding more nodes. But that may not work if your application has single-point dependencies—like a validator API that checks every user request before serving it. A best practice is to identify and remove such bottlenecks in application design as part of the modernization process.
Include security from the start
App modernization may resolve existing security challenges but can also introduce new ones. Cloud providers typically follow a shared-responsibility model. Organizations are responsible for ensuring that cloud configurations are set up correctly and there are no exposed APIs for private data. Having security experts involved in app modernization projects from the start gives more favorable outcomes.
Automate operations
DevOps and DataOps practices form the backbone of modernization efforts. They include setting up tools and technologies that automate day-to-day tasks, like integrating code changes, testing existing code, or cleaning data before integration.
Tools like the Vaadin Modernization Toolkit can transform the modernization process by automatically converting a significant portion of the existing code—up to 80% in some instances. This shift allows developers to focus on refining and enhancing the application, rather than getting bogged down in repetitive tasks, helping your team accelerate their modernization efforts.
Java App Modernization with Vaadin
Vaadin accelerates Java app modernization with two powerful open-source frameworks. Vaadin Flow allows developers to build full-stack web apps entirely in Java, optimizing user experience and scalability.
- Rehosting: Vaadin leverages W3C standards, making applications portable across cloud platforms with minimal changes.
- Refactor & Rearchitect: Vaadin enables easier migration to a server-side execution model for enhanced performance on the JVM.
- Rebuild: Vaadin supports flexible architecture patterns, simplifying large-scale rebuilds with future scalability in mind.
For more insights, download our white paper on Swing-to-Web migration, which outlines a five-step approach to successful modernization.
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