Why Modern Java Broke Struts — and How to Keep Your Apps Running on Today’s Servers

Struts 1.3 and 2.x weren’t built for the world we’re living in now. The Java ecosystem has undergone such dramatic changes over the last decade that the assumptions these frameworks rely on no longer exist. And that shift has pushed thousands of stable, business-critical Struts applications into a dangerous corner: they’re too old to run on modern servers, but too expensive to rewrite.

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The javax → jakarta Namespace Cliff

Modern Java servers are dropping key capabilities your app depends on. Classloader behavior is different. Reflection access is locked down. Security hardening breaks legacy multipart and XML parsing. Even Commons libraries behave differently under new isolation models.

The most significant fracture came from the jump from Servlet 4.0 (javax) to Servlet 5.0 (jakarta). This wasn’t a simple rename—it was a breaking change. If any part of your Struts 1.3 or 2.x app still relies on the javax namespace, it will not run on Tomcat 10+, Jetty 11+, WildFly 27+, or any modern server going forward.

One dependency is enough to break the entire runtime.

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Why Rewriting Struts Isn’t a Realistic Upgrade Path

This is where teams get stuck.

You can’t stay on old servers forever—Tomcat 8.5, Tomcat 9, Jetty 9, and WildFly 26 have real EOL timelines and shrinking CVE coverage. But upgrading Struts the traditional way isn’t simple either. Modernizing past Java 8 means wrestling with removed classes, new isolation models, broken classloader assumptions, deep framework rewrites, and third-party libraries that never made the jump to jakarta.*.

Rewriting a stable Struts app into Struts 6 (or any modern framework) is often a year-plus project with high regression risk and unclear ROI.

Most organizations don’t have the people, time, or budget to take that gamble—especially when the app still works fine today.

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The Modernization Gap: Why Teams Feel Trapped

The problem isn’t a lack of desire to modernize. It’s a lack of safe, realistic options.

For years, teams have had to choose between:

• staying frozen on aging infrastructure
  
  
• rewriting the entire application
  
  

Both paths are costly. Both introduce risk. Neither solves the root problem fast enough.

What was missing was a path that lets teams modernize the platform without rewriting the application itself.

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How Forward Compatibility Solves the Jakarta Breakage

That’s exactly why HeroDevs built NES for Struts: Forward Compatibility.

Instead of forcing teams into a rewrite, Forward Compatibility bridges the compatibility gap—letting Struts 1.3 and 2.x apps run safely on modern Servlet 5.0+ servers without touching application code.

You keep your existing Struts version.
You move to Tomcat 10+, Jetty 11+, or WildFly 27+.
You avoid the jakarta rewrite entirely.

With fully tested binaries, active CVE remediation, and compliance-grade patching, you modernize your stack on your terms—while keeping your application stable and unchanged.

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The Safer Path Forward

Modernization shouldn’t require a massive rewrite or a leap of faith. Forward Compatibility gives you a way to modernize the infrastructure around your app while keeping the app itself intact.

If you’re running Struts 1.3 or 2.x and you’re pinned to outdated servers, this is your way out of the trap. No refactor. No downtime. No jakarta cliff.

Want to explore your modernization path? Let’s map out your safest next step.