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⚡ Java 8 stuck? We fix it.

Java Legacy Modernization – From Java 8 to Spring Boot 3

Your Java 8 application is unmaintainable, the build pipeline is broken, and no one wants to touch the code? I migrate step-by-step to Spring Boot 3 – with React frontends and clean architecture.

Start your migration → Free legacy code check What I do
🛡️ Legacy apps stabilized
🧠 AI refactoring specialist
💸 Fixed pricing & clarity
Java 17+ React PHP 8 Spring Boot JavaScript/TS

❌ "Our AI prototype is not deployable"

❌ "Legacy PHP keeps breaking"

✅ Solution: Refactoring + modern React UIs

My Specializations

▶ Home ▶ Java Legacy ▶ PHP to React ▶ AI Code Refactoring
Java Legacy expertise

Your Java modernization roadmap

From Java 8 to Spring Boot 3 – with React frontends, automated tests, and CI/CD pipelines.

🏚️→🏗️

Java 8 → Spring Boot 3

Step-by-step migration from Java 8 / Jakarta EE to Spring Boot 3 with Java 17+. Modular, testable, and deployable in containers.

Java → Spring Boot PHP → REST API React Frontend
🤖→🧑‍💻

React Frontend for Legacy Backends

Your Java backend is solid but the UI is outdated? I build a modern React frontend with TypeScript, state management, and responsive design.

OpenAI Integration Security & RBAC Deployment Ready
🔁🧹

CI/CD & DevOps Setup

Broken builds, manual deployments, no monitoring? I set up GitHub Actions, Docker Compose, and automated testing for your Java project.

React + Hooks State Management Responsive Design
Common Java pitfalls

Problems I solve for you

  • ✖️ Unmaintainable Java monolith → modular Spring Boot
  • ✖️ Outdated JSP/JSF frontend → modern React SPA
  • ✖️ Unmaintainable "copy-paste" chatbot code
  • ✖️ Security vulnerabilities → OWASP-compliant code

Result: A modern, maintainable, and deployable Java application.

"I already had 3 AI prototypes built — none of them runs in the cloud."

– That is exactly where I step in.

Java migration results

Real Java modernization cases

📉 Before: PHP monolith with 12k lines, no testing, constant outages.

📈 After: API-first architecture + React dashboard, outage rate -95%.

✓ Legacy modernization in 6 weeks

🤖 Before: AI-generated React app without backend — data only in localStorage.

⚡ After: Complete Java Spring API, PostgreSQL, JWT auth + clean UI.

✓ AI integration & production rollout

Java Legacy — FAQs

"How long does a Java 8 → Spring Boot 3 migration take?"

Depends on the codebase size. A typical 50k-line application takes 6-12 weeks. I work incrementally — you see results after each sprint.

"Do you rewrite everything from scratch?"

No. I use the Strangler Fig pattern — gradually replace legacy components while the system stays running. Low risk, continuous delivery.

"What about the database?"

I handle schema migrations, from legacy SQL to JPA/Hibernate, with Flyway/Liquibase for version control. Your data stays safe.

Portrait von Joerg Loos, Fullstack Freelancer für Legacy-Modernisierung und KI-Integration
About me

Java Legacy modernization specialist with 10+ years experience

I have been developing Java applications for over 10 years — from Java 5 to Java 21. I know the pitfalls of legacy migrations and ensure a smooth transition.

Stack: Java 8-21, Spring Boot 3, Hibernate, Docker • Approach: pragmatic, transparent, production-focused.

Java legacy burden?

30 minutes free analysis of your Java legacy — I will create a migration plan.

Send email: kontakt@jloos.dev

or via LinkedIn / Xing — contact details on request