Upwork home
Sign up
Project Catalog
DesignDesign
Video & AudioVideo & Audio
Development & ITDevelopment & IT
MarketingMarketing
Writing & TranslationWriting & Translation
MoreMore

You will get a modernized, fully migrated legacy Java application

Attila B.Status: Offline
Attila B.
Preview imagePreview imagePreview image

Let a pro handle the details

Buy Web Application Programming services from Attila, priced and ready to go.
Attila B.Status: Offline
Attila B.
Preview imagePreview imagePreview image

Let a pro handle the details

Buy Web Application Programming services from Attila, priced and ready to go.

Project details

Running an old Java or Spring application that has become risky to maintain or hard to extend? I migrate and modernize legacy Java systems to current, supportable versions without breaking what already works. With 20 years of enterprise Java experience across fintech, retail, and media industries, every engagement starts with a structured technical analysis of the existing codebase and a migration plan, so you know the risks and steps before any code changes begin.
Programming Languages
Java
Coding Expertise
Performance Optimization, Security
What's included
Service Tiers Starter
$90
Standard
$240
Advanced
$490
Delivery Time 5 days 12 days 25 days
Number of Revisions
123
Design Customization
-
-
-
Content Upload
-
-
-
Responsive Design
-
-
-
Source Code
Optional add-ons You can add these on the next page.
Fast Delivery
+$40 - $120
Additional Revision
+$30
Database Integration (+ 1 Day)
+$25
API Testing Extra (+ 2 Days)
+$40
Observability Setup (+ 3 Days)
+$60

Frequently asked questions

Attila B.Status: Offline

About Attila

Attila B.Status: Offline
Senior Software Engineer | Java/Spring Boot, React Native & AI/LLM
Godollo, Hungary - 10:46 pm local time
Meticulous and reliable software engineer with over a decade of experience delivering international IT projects, from backend microservices to AI-driven applications. I specialize in Java/Spring Boot backend development, Kubernetes-based microservice architectures, and increasingly in AI/ML solutions including retrieval-augmented generation (RAG) pipelines and large language model integration.

Recent work includes leading development of a Kubernetes-based core banking integration platform, building AI-powered search and risk-assessment tools using transformer models, and delivering a React Native mobile ticketing app for a public transport tender.

Core strengths: crisis management, systems architecture and planning, project and team leadership, and adapting quickly to new technologies under tight deadlines. Comfortable across the full stack: Java, Python, TypeScript/React, mobile (React Native), CI/CD (GitLab, Jenkins), containerization (Docker, Kubernetes), and major databases and message queues.

I thrive in agile environments and enjoy solving complex technical problems, from legacy system modernization to cutting-edge AI integration.

Steps for completing your project

After purchasing the project, send requirements so Attila can start the project.

Delivery time starts when Attila receives requirements from you.

Attila works on your project following the steps below.

Revisions may occur after the delivery date.

Codebase analysis and migration assessment

I analyze your codebase, dependencies, and risk areas, and produce a migration roadmap.

Module migration and implementation

I migrate the agreed module(s) to current Java and Spring Boot versions, adding tests along the way.

Review the work, release payment, and leave feedback to Attila.