How to Modernize 30-Year-Old Java Apps for the Next 30 Years
Java has been the backbone of web and enterprise applications for 30 years, powering everything from banking systems to large-scale logistics platforms. Not only is the technology still widely used, but some of the earliest enterprise Java applications developed in the 1990s and early 2000s are still running, playing a key role in business operations. So, how can developers bring these essential 30-year-old enterprise Java applications into the future without disrupting critical business functions?
As we celebrate 30 years of Java, let’s time travel back to the mid-1990s. I remember my father had just started a new job at a company providing IT outsourcing services to banks—or, as I used to explain to my classmates, “he works with computers.” At the time, his new workplace was buzzing about the “cool Sun reps” and the new kid on the block: Java.
The promising “Write Once, Run Anywhere” (WORA) magic was fascinating many software developers, who were eager to build robust enterprise applications based on this exciting new technology. Countless engineering teams across the world succeeded in establishing the Java language and its framework as the de facto standard for application development. These first applications set the foundation for digital business operations as we know them today.
Fast forward three decades, and my father is about to retire while these very same Java applications are still there, together with many other newer ones. In many cases, these earlier software solutions can be considered ‘legacy,’ as they were developed with older technologies or using outdated development paradigms. As such, these once cutting-edge applications are now often suffering from a number of issues, such as outdated architecture and security vulnerabilities. Moreover, they can be challenging and/or costly to maintain.
Bite the bullet: If it ain’t broke… it may still need fixing
Legacy applications aren’t necessarily broken. In fact, they remain critical to many day-to-day operations and are still functioning well—just not well enough for today’s business and technology requirements.
An enterprise Java application written in the early 2000s on Java 2 Platform, Enterprise Edition (J2EE) or Java EE might still be effectively handling financial transactions or managing logistics. However, integrating it with modern tools and platforms, ensuring their security and next-level performance can be challenging if not impossible. Add to that the dwindling number of experts that were involved in the initial creation of the legacy applications and the limited pool of developers familiar with older Java versions, and you have a task that becomes harder to tackle with each passing year.
Because of the crucial role such legacy applications have, the question isn’t whether they need modernization, it’s how to do it while minimizing any interference with the entire system and associated business operations. Luckily, there are a number of ways to successfully upgrade.
The best approach to modernization should take into account business objectives, budget constraints and the risks involved. Some organizations may prioritize cost-effectiveness and opt for incremental updates, while others may focus on long-term scalability and choose a complete overhaul.
What to consider before modernizing
Understanding different migration approaches as well as how they can both address technical and business needs is at the backbone of any successful modernization. By having a clear picture of the current status and what’s needed, companies can set up effective plans that align with strategic goals while maximizing returns on investment and mitigating potential disruptions.
When discussing the potential modernization of an enterprise Java application, it is important to inspect the software and define the potential technical challenges that may arise. These can be caused by legacy dependencies, outdated frameworks or monolithic architectures that can be difficult to decouple. Moving to modern frameworks can introduce complexities that require careful planning. Additionally, security vulnerabilities in older Java applications can present risks if they are not properly addressed during the modernization process.
Budget should also be discussed. While modernization comes with significant costs for infrastructure, licensing, training and potential downtime, there are multiple routes available, each involving different initial investments. In addition, organizations should weigh the short-term expenses against long-term gains, such as reduced maintenance costs, improved security and uptime as well as the ability to support future business growth.
Besides, cultural issues should be evaluated too. Developers may be keen to adopt the latest technologies, while business leaders may hesitate to invest in something that appears to be “working fine.” Bridging this gap requires clear communication and extensive collaboration, so that all expectations are managed, and everyone understands the value of an up-to-date application.
In addition to assessing and building the right modernization culture, it is important to consider developer talent. Java remains one of the most popular programming languages and frameworks, but the expertise associated with enterprise Java applications written in the 1990s and early 2000s is dwindling. The original developers of legacy systems are no longer available to consult. Like my father, many of them are now enjoying their retirement.
This fact, combined with limited documentation from earlier systems, means that reverse engineering is often essential before updating an application. In addition, the software may rely on outdated frameworks and methodologies that current teams may not be experienced with. Having a clear picture of the existing capabilities and any potential gaps is fundamental to defining how to proceed.
By proactively discussing and planning these aspects, organizations can identify the most suitable modernization strategy and set the stage for a successful collaboration.
The many paths to modernization
For some businesses, the best approach is the least disruptive. In such cases, retention, also known as encapsulation, is ideal. It involves keeping the old system intact but wrapping its core features within one or more microservices that interact with newer applications offering more modern capabilities. As a result, it is possible to maintain the necessary functionalities without any rewrite while adopting innovative elements, such as cloud-based enhancements.
Another non-invasive option is rehosting, also known as lift-and-shift. It typically involves migrating an application from one physical environment, such as on-premises hardware, to another, namely a cloud infrastructure. The process focuses solely on the hosting environment and doesn’t involve any significant changes to the application’s underlying architecture or functionality.
While this approach offers a quick way to transition to a new environment and can partially help reduce the cost of maintaining aging hardware, it may not help developers and end users fully leverage the benefits of the cloud (or any other new platform). Therefore, they may not be able to benefit from key modernization opportunities, such as system optimization, new capabilities and further cost savings, that could be achieved through more extensive modifications.
A step in this direction can be achieved by opting to replatform legacy applications, which involves migrating the legacy application to a newer version of its runtime without making extensive changes to the code or its structure. This update helps companies take advantage of modern improvements while keeping the application largely intact. For instance, an application running on Java 5 and J2EE could be upgraded to Java 11 and Jakarta EE 8 with minimal modifications. While this might seem like a small change, the performance enhancements and security updates are substantial and can help minimize security risks.
Organizations can also combine replatforming with refactoring, which involves optimizing and restructuring an application internally, i.e. its source code, without impacting its external functionality and intended functions. The goal of this type of modernisation is to improve the internal performance and maintenance of the application without causing significant downtime. For example, moving J2EE applications to the Cloud can breathe new life into an aging system without having to invest in a complete rewrite, even if the updated solution doesn’t take full advantage of the new environment.
When the goal of a modernization is shifting to a different architecture, e.g. from monolithic to microservices-based applications, then a rearchitecting is necessary. By breaking a monolithic Java application into microservices, companies can improve their systems’ scalability, independence when it comes to deployment, as well as resilience in case of failures.
Rather than updating just part of a legacy enterprise Java application to adopt more modern architectures and innovations, such as the cloud, organizations may have the resources needed to rebuild the application. This involves rewriting the entire code and it can help fully leverage the latest technologies at hand.
Finally, the most radical approach is the full replacement of the existing enterprise Java application. Starting from scratch with modern Java frameworks and technologies can certainly help companies interested in staying up to date with the latest solutions and trends. However, while this guarantees a fresh start with the latest capabilities, it also demands significant investments in terms of cost, time and resources. Organizations must carefully weigh whether the benefits of a ground-up replacement justify the disruption.
Although the modernization approaches discussed here vary, certain strategies can help ensure success regardless of the chosen path. For example, adopting a phased approach, even when rebuilding or replacing legacy applications, can help minimize disruptions. Gradually introducing new technologies, e.g. through incremental updates and proof-of-concepts, allows teams to adapt at a manageable pace and make sure that the entire system and associated applications continue to work smoothly.
Adopting a modernization mindset
Java and enterprise Java applications from the 1990s and early 2000s are the backbone of a multitude of today’s digital systems. As such, keeping them up to date is paramount to ensure optimum operations, delivering high performance, efficiency and uptime while maximizing user satisfaction.
While application modernization is inevitable, the goal of such activity isn’t to blindly update old code or adopt any new technology available. Successful modernizations are first and foremost strategic, as they balance innovation with pragmatism. Not every system needs a microservices overhaul, nor does every modernization effort require a full rewrite. With careful planning and the right strategy, even a 30-year-old Java application can be ready for the next 30 years.
