Jose Ignacio L.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

Senior Java developer with 19 years on production Java (Java 6 to 25). I maintain and modernize long-lived Java web applications: JBoss, Seam, JSF (RichFaces, PrimeFaces), Struts and JSP on the legacy side; Spring Boot, React and PostgreSQL on the modern side. WHAT I DO • Fix production bugs in existing Java codebases, including code nobody on the current team wrote • Add features, integrations and reports to a live product without stopping it • Make an unbuildable legacy build reproducible again: containerized, running locally and in CI • Modernize step by step: a Spring Boot + React layer that takes over from JSF, Seam or JSP one feature at a time, or an automated JSF migration (RichFaces to PrimeFaces) • Add AI to an existing product safely: MCP servers in Spring AI, with OAuth 2.1 so every agent action runs with the real user's permissions EXPERIENCE • Dynamtek, laboratory information system vendor (2018-2022, hired through Upwork): fixed production bugs in a JBoss Seam + JSF system that handles blood test results. Built a tool that migrated the entire RichFaces front end to JSF 2 + PrimeFaces automatically, rewriting every XHTML file and refactoring the Java sources, so a months-long manual migration became a repeatable process. Added a React front end for patient invoicing. • Dynamtek again (2024-present): they came back for the product's new version on Spring Boot 4, React 19 and PostgreSQL. I own the architecture, review other developers' code, designed the multi-tenant production deployment (one schema per client, versioned containers, rollback playbook) and built the MCP server that exposes the product catalog to AI assistants. • Indeed, through AgileEngine (2022-2024): backend engineer (Java, Spring, React) on an internal compliance platform, working daily in English inside a distributed US team. • National government agency, Argentina (2008-2024): 16 years on a nationwide transactional platform built on Java, JBoss Seam, Hibernate and Oracle. Tech lead and architect from 2020: designed the integration contract that provincial government systems implement, and led the incremental migration of the front end off JSF while the system stayed in production. HOW I WORK • Written scope first: deliverable, acceptance criteria, access needed and an hour cap • Asynchronous and written-first; short calls with an agenda when they help • AI coding agents do the mechanical work; I review every change, and each change ships with notes your team can support • Your team keeps production ownership; no 24/7 on-call AVAILABILITY • 20 to 30 hours per week, long-term engagements preferred; happy to start with one small paid task • Based in Argentina (UTC-3), with working hours that overlap US Eastern time • Professional working English, written-first GOOD FIT: a Java product with paying customers whose original developers are gone or busy; a production bug, a broken build, or a legacy module that has to move to Spring Boot and React. NOT A FIT: new mobile apps, WordPress or PHP sites, 24/7 support contracts. STACK: Java 6-25, Spring Boot, Spring AI, Spring Security, Hibernate/JPA, JBoss/WildFly, Seam 2, EJB3, JSF (RichFaces, PrimeFaces), Struts 2, React, TypeScript, AngularJS, PostgreSQL, Oracle, Flyway, GraphQL, REST, Docker, Maven, Gradle, JUnit 5, Testcontainers, Playwright, Model Context Protocol (MCP).