Legacy Java Modernization
Modernize Java EE, JBoss, WebLogic and older Java applications incrementally, without a risky full rewrite.
Available for consulting & engineering projects
Java Backend Engineer
Software Modernization Consultant
Modernize your Java system without rewriting everything from scratch.
I'm Vadim Rodionov. I help companies modernize legacy Java systems without risky rewrites — improving performance, stability and maintainability while keeping production running.
No commitment. Tell me what you're dealing with and I'll tell you where I'd start.
6+
years of Java backend development
40–50K
daily users on national-scale systems
Tens of TB
of data processed and stored
High-load
distributed enterprise systems
Services
What I do
I work where existing systems meet new requirements — improving what's already in production instead of starting over.
Architecture & Migration
Design migration strategies, introduce modern services and gradually move systems toward Spring Boot and distributed architectures.
Performance & Scalability
Find bottlenecks, investigate production problems and improve systems operating under high concurrency and tight resource constraints.
Production & Integration
Troubleshoot critical production issues and modernize integrations involving legacy systems, APIs, messaging and databases.
Legacy System Assessment
Analyze your existing architecture, identify technical risks and bottlenecks, and provide a practical modernization roadmap.
Start with an assessmentModernization path
Legacy doesn't have to mean starting over.
The safest path is usually incremental: keep the system running, isolate what's risky, and replace it step by step while legacy and modern components operate in parallel.
Legacy system
- Java EE
- JBoss / WebLogic
- Oracle
- SOAP / XML
- Monolith
Modern system
- Java 11+ / Java 25
- Spring Boot
- Microservices
- Kafka / RabbitMQ
- PostgreSQL
- Docker / Kubernetes
- CI/CD
You don't have to throw everything away. In practice, legacy and modern cores can run side by side for as long as it takes to move safely — with no visible impact on end users.
Problems I solve
Does your system look like this?
- Nobody fully understands how parts of it work anymore.
- A seemingly small change breaks something somewhere else.
- The application becomes unstable under increased load.
- Developers spend too much time maintaining old infrastructure.
- You have JBoss, WebLogic or Java EE applications that need modernization.
- A full rewrite would be too expensive or too risky.
- Legacy systems need to coexist with new services.
- Production problems are difficult to reproduce and diagnose.
I specialize in making these systems manageable again.
Understanding the system as it is, reducing risk step by step, and keeping production stable while it changes.
Experience
Where I've done this
ARTA Limited
Feb 2026 — Aug 2026
Senior Java Software Developer
Enterprise low-code platform used by businesses to automate processes.
- Built a new application core in Java 25 and Spring Boot as part of migrating the platform off a legacy Java EE core.
- Designed a gradual migration strategy so legacy and modern cores operated in parallel with no visible impact on users.
- Optimized the platform to support around 7,000 concurrent users on tightly constrained infrastructure.
- Identified and fixed security vulnerabilities, contributing to a successful security certification in Kazakhstan.
- Worked as one of three senior backend developers, with primary responsibility for the application core.
Esepshi.kz LLP
Feb 2020 — Dec 2025
Java Software Developer / Senior Java Developer
National-scale government information systems for the State Revenue Committee of the Republic of Kazakhstan.
- Worked on a large distributed tax information system serving 40,000–50,000 daily users, handling hundreds of thousands to millions of requests per day and tens of terabytes of data.
- Designed and built microservices with Java 11, Spring Boot, Spring Cloud, Kubernetes, Docker and PostgreSQL.
- Maintained and modernized legacy components based on Java 7/8, WebLogic, SOA/OSB, Oracle, SOAP/XML and PL/SQL, including Java 7 → 11 migrations.
- Integrated legacy systems with modern microservices across independent government information systems.
- Investigated and resolved critical production issues across application code, databases, infrastructure and distributed components.
- Set up CI/CD, monitoring and logging; conducted code reviews, led two junior developers and ran technical interviews.
Technology
Tools I work with
Not a badge collection — the stack I use to keep legacy and modern systems running together.
Core technologies
- Java 11–25
- Spring Boot
- Spring Cloud
- Kafka
- RabbitMQ
- PostgreSQL
- Oracle
- Kubernetes
- Docker
- Linux
- GitLab CI/CD
- Elastic Stack
Legacy expertise
- Java EE
- JBoss
- WebLogic
- ActiveMQ
- SOA / OSB
- SOAP · XML · XSD · XSLT
- PL/SQL
Most engineers pick one side. I work across both — and that's usually exactly what these projects need.
About
About me
I'm a backend engineer with 6+ years of experience building and modernizing enterprise Java systems.
Most of my work has been at the intersection of legacy and modern architecture — keeping existing systems running while gradually replacing outdated components with modern, scalable services. I've worked on government-scale platforms where downtime isn't an option, and on enterprise products where migration had to happen without users noticing.
I enjoy difficult technical problems: understanding systems I didn't design, finding out why they're slow or unstable, and improving them without breaking everything around them.
Quick check
Is your system a candidate for modernization?
Four questions, no email required.
Are you running Java 8 or older?
Do you use JBoss, WebLogic or another Java EE application server?
Is your application a large monolith?
Does it struggle to scale or stay stable under load?
Contact
Have a Java system that needs modernization?
Tell me what you're dealing with — the stack, the symptoms, the constraints. I'll take a look and we can discuss whether I can help.
No commitment. Tell me what you're dealing with and I'll tell you where I'd start.
- Email rodionov@tuta.io
- LinkedIn linkedin.com/in/vadim-rodionov
- Telegram @rodionov_vadim
- CV Download PDF
Astana, Kazakhstan · GMT+5 · available for remote work worldwide