Your Java migration isn't stuck because it's hard. It's stuck because nobody knows how big it is.

Almost every telecom and fintech engineering team I talk to has the same ticket in their backlog: "Upgrade to Java 17/21 and Spring Boot 3." It has been there for a while. It gets discussed in planning, everyone agrees it matters, and then it slides to next quarter again.

The reason is rarely a lack of skill. It's a lack of visibility. Nobody can say with confidence how many services will break, which dependencies have no Jakarta-compatible version, or whether the regression tests will actually catch a problem. Without those answers, the estimate is a guess, and no engineering manager wants to pull developers off the roadmap for a guess.

That is exactly the problem the Legacy Java Audit solves.

What is the Legacy Java Audit?

The Legacy Java Audit is a focused, fixed-scope assessment of your Java backend. It answers three questions before you commit a single sprint to modernization:

1. What breaks when you move from Java 8 to Java 17/21 and from Spring Boot 2 to Spring Boot 3?
2. How risky is each service, and why?
3. In what order should you migrate, so feature delivery never has to stop?

It's the first step of my Rapid-Sprint Modernization Protocol, and it's designed to give you real numbers instead of assumptions.

What the audit covers

1. Java version compatibility (Java 8 → 17/21)

Jumping from Java 8 to Java 21 crosses several breaking changes, and legacy enterprise code tends to hit most of them:

• Removed Java EE modules. JAXB, JAX-WS, and related APIs were removed from the JDK in Java 11. SOAP-heavy telecom systems depend on these more than most teams realize.
• Internal JDK APIs. Code (or libraries) using sun.misc.* and other internal APIs is strongly encapsulated from Java 17 onward. I scan for these with jdeps and flag every usage.
• Removed and deprecated features. For example, the Nashorn JavaScript engine (removed in Java 15) and the deprecated Security Manager.
• Runtime workarounds. Existing --add-opens flags and reflection tricks that will need a proper fix.

2. Spring Boot 2 → 3 and the javax → jakarta migration

Spring Boot 3 requires Java 17 as a minimum and moves from javax.* to jakarta.*. Spring Boot 2.7 reached the end of its open-source support in November 2023, so staying put is a growing risk. The audit maps:

• Every javax.persistence, javax.servlet, javax.validation, and related import that has to move to Jakarta
• Spring Security configuration that relies on APIs removed in Spring Security 6 (such as WebSecurityConfigurerAdapter)
• Hibernate 6 behavior changes that affect your queries and mappings
• Tracing and observability changes (Spring Cloud Sleuth → Micrometer Tracing)
• Renamed or removed configuration properties

3. Dependency and security review

Most migration surprises come from dependencies, not your own code. I review the full dependency tree, including transitive dependencies, to find:

• Outdated or abandoned libraries with no Jakarta-compatible release
• Known vulnerabilities (CVEs) in your current versions
• Version conflicts that will surface during the upgrade

4. Integration surface (telecom and fintech specifics)

This is where telecom and fintech backends differ from typical web apps. The audit checks the integrations that tend to break quietly:

• SOAP/WSDL clients and services (Apache CXF, JAX-WS)
• Payment gateways, billing systems, and partner APIs
• Message brokers, database drivers, and connection pools
• Serialization formats that partners depend on

5. Test coverage and regression safety net

A migration is only as safe as the tests behind it. I identify which critical flows are well covered and which have no safety net, so we know where to add tests before changing anything.

6. Build, deployment, and CI/CD readiness

Code is only half the migration. I also check Maven or Gradle plugin versions, Docker base images, the JDK used in your pipelines, and deployment targets. For example, Jakarta-based apps need Tomcat 10.1 or later, so an older application server is a blocker of its own.

What you get at the end

You receive a clear, decision-ready report, not a pile of scan output:

• Modernization risk map: every service rated low, medium, or high risk, with the reasons behind each rating
• Blocker list: concrete, file-level findings for each service
• Recommended migration order: a service-by-service sequence that keeps your roadmap moving
• Effort estimate in sprints: realistic numbers you can take to planning or budget approval
• Quick wins: low-risk fixes your team can make now, without touching feature work
• Walkthrough call: a session with your tech lead to go through the findings and answer questions

How the audit works

1. Kickoff call. We agree on scope: which repositories, which services, and your target versions (Java 17 or 21, Spring Boot 3).
2. Read-only access and automated analysis. I run dependency analysis, jdeps scans, and OpenRewrite dry runs against your code. Nothing is changed in your repositories.
3. Manual review. I review the critical paths, integrations, and anything the tools can't judge on their own.
4. Report and walkthrough. You get the report and we walk through it together.

Turnaround: 5-10 working days, depending on the number of services in scope.

Your team keeps shipping the entire time. The only time I need from your side is the kickoff call, repository access, and the final walkthrough.

Who this is for

The Legacy Java Audit is a good fit if:

• Your telecom or fintech backend still runs on Java 8 (or Java 11) and Spring Boot 2.x
• Your modernization ticket keeps getting pushed to next quarter
• You need solid numbers to get budget or leadership approval for the migration
• Security or compliance reviews are flagging outdated dependencies
• You want to modernize without freezing feature delivery

Frequently asked questions

Do you need write access to our code? No. Read-only access is enough. The audit never changes your repositories.

Will this slow down our team? Barely. Your team needs to join the kickoff and walkthrough calls and answer occasional questions. Feature work continues as normal.

We're on Java 11, not Java 8. Is this still useful? Yes. The same audit applies to any Java version below 17 and any Spring Boot 2.x application.

Can you sign an NDA? Yes. I'm happy to sign an NDA before receiving any access.

What happens after the audit? That's up to you. Many teams use the report to plan the migration internally. If you'd like support, the natural next step is a Pilot Migration Sprint, where we migrate one service end to end to prove the approach on your system.

About me

I'm Feroz Khan, a Senior Software Engineer at Seamless Distribution Systems (SDS) with 7+ years of experience building and maintaining enterprise Java backends, particularly in the telecom domain. I work daily with Java, Spring Boot, microservices, REST/SOAP integrations, SQL, and distributed systems. I help telecom and fintech engineering teams modernize legacy Java backends in weeks instead of quarters, without freezing feature delivery.

Get your audit

If your Java 8 backend has become a risk you can't measure, let's measure it.

Get Your Audit Now

Or reach me directly: ✉️ khan.feroz8899@gmail.com ☎ +923244148420