Application Modernization: Key Strategies to Overcome Common Challenges

Many enterprise Java application developers are facing the same challenge: handling the many legacy systems used by their organizations. Modernizing these is critical to improving scalability, performance and security. Yet, many teams are still supporting workloads based on Java SE 8 or earlier versions, despite newer versions and modern frameworks offering significant advantages. This aversity to refreshing such applications stems precisely from the importance these pieces of software have within an organization, as their disruption can considerably impact business operations.  

This blog is your practical guide to successfully navigating that shift: from evaluating legacy codebases to leveraging cloud-native architectures, CI/CD pipelines and runtime tools to futureproof your enterprise Java applications while streamlining key modernization efforts. 

What Is Application Modernization?  

Before looking at how to modernize legacy enterprise Java applications, let’s have a closer look at what application modernizations are and what they involve.  

Application modernization is the process of updating and transforming legacy applications to align with current business needs and technological advancements. 

Application modernizations are all about revitalizing outdated applications to align with current business needs, take advantage of the latest technologies and paradigms and minimize disruptions, without discarding what still works. In practical terms, it means taking older applications, i.e. legacy systems, and improving them in ways that make them: 

• Easier to maintain 

• More secure 

• Scalable and cloud-ready 

• Compatible with modern interfaces, tools and platforms 

• More efficient, in terms of performance and resource usage 

Ultimately, application modernizations help you ensure your software keeps pace with innovation and meets growing expectations, while reducing the risk and cost of starting from zero.  

It’s important to stress that under the umbrella of application modernizations strategies, specific projects can take many forms, such as replatforming, refactoring or rearchitecting. As such, the work required and end results can vary greatly.  

Benefits of Modernizing Applications  

Legacy applications often form the backbone of daily business operations but have become barriers to an organization’s growth, adaptability and/or innovation. They may still work (and they may be relatively new), but they typically suffer from: 

• Performance bottlenecks 

• Security vulnerabilities 

• Incompatibility with modern systems 

• High maintenance costs 

• Limited scalability and agility 

Modernization addresses these issues while preserving the application's core value. Thus, it can offer a strategic investment with wide-reaching benefits across the business. More precisely, by modernizing your legacy applications, you can: 

• Improve agility, as modern systems are typically easier to change, test and deploy  

• Reduce operational and maintenance expenses associated with outdated systems, which are generally more challenging to maintain and fix 

• Leverage modern technologies for better performance, scalability and reliability 

• Enhance security and compliance, as you can make sure you are relying on modern security best practices, meet regulatory requirements and patch vulnerabilities more easily with modern tooling 

• Improve integration with other apps and modern ecosystems 

Challenges of Application Modernization  

Modernizing legacy enterprise Java applications promises big benefits, but it also comes with real challenges. According to a recent survey, 93% of IT leaders found their modernization experience was extremely or somewhat challenging. Understanding the main hurdles up front can help organizations plan smarter and reduce risk during transformation efforts. These typically include: 

• Complex legacy architecture and lack of documentation or software knowledge. Many legacy systems were built before documentation was a priority or that knowledge has since left the organization. As such, it can be difficult to isolate features or modules. Also, business logic may be buried in the code 

• Ensuring seamless integration with existing systems, as apps are often deeply integrated with other systems, databases and internal tools, so the risk of breaking connected systems during modernization is real  

• Addressing the need for expertise in new technologies. In addition to missing legacy app-specific knowledge, the team may be unfamiliar to more modern solutions. Upskilling, hiring new talent and/or the adoption of new tools may be necessary 

• Safely transferring data without loss or corruption 

Strategies for Application Modernization  

So how do you modernize intelligently and successfully? Let’s walk through proven strategies to modernize legacy enterprise Java applications, reduce technical debt and maximize long-term business value.  

1) Comprehensive Application Assessment 

Before even thinking about touching a line of code or deploying a container, you need a clear understanding of your current state. A comprehensive assessment is the foundation of any successful modernization effort. 

Evaluate Your Existing Applications 

Begin by auditing your portfolio of applications and systems. Key areas to assess include: 

• Business value: Is this application still core to operations? 

• Technical debt: Are there outdated frameworks or unsupported libraries? 

• Performance and stability: Are there recurring issues or slowdowns? 

• Integration dependencies: How tightly coupled is it with other systems? 

Involve both technical teams and business stakeholders to get a full picture of an application’s usage, criticality and pain points. 

Determine ROI Potential 

After reviewing your application, it’s time to think about the resources needed vs. those available. Estimate potential returns such as: 

• Reduced infrastructure or licensing costs 

• Improved team productivity and faster releases 

• Better customer experience or increased revenue 

• Risk mitigation (e.g., security compliance, system failures) 

Modernization isn’t free, so maximizing the investment is crucial. Assign priorities based on both business impact and modernization effort. Focus first on applications that are easier to modernize but whose upgrade can have high returns on investment (ROI). This strategy can help the team to successfully complete the project while enhancing their skills to modernize more challenging systems in the future. 

2) Choose the Right Modernization Strategy 

Based on the results obtained from the two analyses above, you can identify the modernization strategy that is best suited to address your specific requirements, such as goals, resources and timelines. You may opt for anything between retaining/encapsulating your apps or replacing them. If you are unsure about the options available, download our free guide “A Business Guide to Legacy Application Modernization For The Cloud Era” for direction. 

3) Identify the Right Technologies  

Once you've committed to modernizing your applications, the next big question is: what will you modernize with? It’s important to select the right solutions strategically. Don’t just reach for what’s new, but what fits your business, your systems and your people. The tools and platforms you choose will shape not only how smoothly the transformation goes, but how maintainable, scalable and future-ready your systems will be in the years to come. 

For many organizations, the right technologies revolve around microservices, containers and cloud-nativeness. However, you should favor platforms that don’t force you into all-or-nothing decisions. For example, Payara Server Enterprise allows teams to support both modern Jakarta EE workloads and existing Java EE applications, side by side. Similarly, Payara Platform Enterprise support on-premise, cloud and hybrid deployments. Through these opportunities, you can make sure you are updating incrementally, preserving mission-critical systems while slowly evolving your applications. 

Implement CI/CD 

The same careful selection applies to your delivery pipeline. As DevOps and GitOps become the norm, continuous integration and continuous deployment (CI/CD) practices can transform how you manage updates, such as automating testing, enforcing quality and speeding up releases. But here too, it's about choosing tools that align with your workflows, integrate easily, and help you scale efficiently without adding complexity. 

4) Ensure Robust Security Measures 

Security must be built in your migration plant, rather than bolted on. Legacy applications may have unknown vulnerabilities, hardcoded credentials or unpatched dependencies. A number of these can surface during modernization activities and new ones can be introduced if you're not careful.  

Incorporating security best practices throughout the modernization process can help overcome key challenges and enhance the robustness of your application. In particular, make sure you protect your applications during and after modernization through data encryption in transit and at rest, role-based access control (RBAC) as well as regular vulnerability scans and code audits. 

Payara's Role in Application Modernization: Real-World Success Stories 

Payara Services is a trusted partner for organizations seeking to modernize their legacy applications while maintaining their more modern workloads, streamline operations and future-proof their technology stacks. Through its robust middleware application platform, broad technology compatibility and responsive support, Payara has enabled organizations across multiple industries to overcome modernization challenges and achieve tangible business outcomes. 

SIFMA Foundation: Scaling Operations and User Growth 

The SIFMA Foundation faced significant hurdles with an outdated, unsupported proprietary middleware that limited scalability and modernization. By migrating to Payara, the SIFMA Foundation was able to: 

• Transition to a reliable, customizable Java-based configuration 

• Simplify updates, patches, and system improvements 

• Quadruple its user base after modernization  

Learn more

CDL: Strategic Migration for Innovation 

Insurtech leader CDL sought to re-engineer its flagship platform to deliver advanced capabilities and maintain a competitive edge. Migrating to Payara Server Enterprise enabled CDL to: 

• Seamlessly shift from their previous application server while ensuring data integrity and regulatory compliance 

• Enhance operational efficiency and customer experience 

• Position the company at the forefront of insurtech innovation 

Read more  

Rakuten Card: Towards Microservices and Beyond 

Leading credit card provider Rakuten Card partnered with Payara Services to modernize its IT infrastructure as part of a strategic shift to the cloud. Modernization has enabled Rakuten Card to: 

• Move from a large monolithic application hosted on a traditional enterprise Java application server to a microservices architecture 

• Benefit from a lightweight, cloud-native middleware solution that aligned with modern application development practices while providing greater scalability and resilience 

• Improve availability, reliability, resource utilization as well as faster deployment cycles 

Read more 

These real-world cases underscore our commitment, expertise and key role in successful application modernizations that enable rapid user growth, operational scaling and the delivery of robust, resilient architectures for future-oriented applications. 

What's Next in Your Modernization Journey

Want to learn more and gain real-world, practical insights on how to succeed in your legacy application modernization projects? Join our Payarans online on August 20th for a live webinar on the topic. Save your spot here.