24.07.2026 aktualisiert
Premiumkunde
100 % verfügbarSenior Fullstack Software Engineer
Pulheim, Deutschland
Pulheim +100 km
Diplom Informatiker (FH)Über mich
Seit 2005, nach meinem Informatik Studium (Diplom FH) habe ich in mehreren Branchen gearbeitet, schwerpunktmässig im Backend Bereich mit Java. Wobei ich immer wieder auch in Frontend Bereiche tätig war. Seit 03.2019 bin ich Freelancer.
Skills
JavaJavaScriptAndroidHibernateJUnitPostgreSQLApache MavenMySQLRedisSwaggerSQLitePL/SQLSQLTypeScriptOpenapi
Java, Kotlin, SQL, PL/SQL, JavaScript/TypeScript, Groovy, C#,
PHP , Python, [Dart, Ruby, Go]*,
Spring, Spring Boot, Spring Batch, JEE, Quarkus, JPA,
Hibernate, Toplink/EclipseLink, PHP Symfony, JMS, SSE,
WebSockets, REST, SOAP WebServices, TIBCO ESB, [Vert.x]*,
Android, JSF/PrimeFaces, Vue.js, Ember.js, React, GWT, JSP , Struts,
Swing, Java-Applets, htmx, HTML, CSS, [Polymer-JS,
Angular.js, Vaadin, ActionScript/Flex]*,
Elasticsearch, Oracle DB, MySQL/MariaDB, PostgreSQL,
Sybase, MS SQL Server, H2, SQLite, Redis, Firebase, Firebird,
Tomcat, JBoss, Glassfish, Oracle WebLogic, Infinispan Cache,
Maven, Ant, Gradle, Git, Subversion, Jenkins, Docker,
OpenAPI/Swagger,
JUnit, Selenium, Mockito, JMeter, MapStruct,
IntelliJ IDEA, Eclipse, Android Studio, VS Code,
Google Maps on Android, HERE Maps on Android,
Highcharts-JS, [WebRTC]*
[marker for spare time experience level]*
Sprachen
DeutschverhandlungssicherEnglischgutRussischMuttersprache
Projekthistorie
Legacy System Modernization (Medical Sector)
Analyzed a 20-year-old, large-scale Java/Tomcat application (~2M
LOC) to propose a comprehensive modernization strategy using
AI-assisted tooling.
- AI Migration PoC: Developed a proof-of-concept leveraging AI
models to automate the migration of legacy JSP pages to modern
React components.
- Architecture Audit: Evaluated a custom Servlet-based backend
(no Spring/JEE) with ~0% test coverage; streamlined ongoing
migrations (Firebird to PostgreSQL) and redundant React state
management in a mixed JS/TS codebase.
- Production & Cluster Support: Resolved critical live-system issues
in a clustered environment, focusing on session handling,
Server-Sent Events (SSE), and license counting.
- Tech Stack: Java 11, Tomcat 9, Redis, PostgreSQL, Firebird, React
(JavaScript/TypeScript), Docker Compose, Claude, Codex, Gemini
CLI, IntelliJ.
Focused on upskilling and hands-on deep dives into
emerging technologies to expand my freelance service
portfolio. Developed several proof-of-concepts (PoCs)
and independent projects, including:
- CMDBlite: A lightweight, multi-tenant CMDB system with
integrated monitoring capabilities.
Tech Stack: Java, Quarkus (native build), SQLite, plain JavaScript,
htmx, Qute templating, Server-Sent Events (SSE), Docker.
- HN Client for Hacker News (Published Android App): A
minimalist Hacker News reader featuring a custom archive
function.
Tech Stack: Kotlin, Ktor-Client, Room (SQLite), Google Firebase,
on backend: Quarkus, REST, SQLite.
- AI Integration & Tooling: Evaluated capabilities and integration
patterns of the Gemini CLI AI tool.
Software architecture, development
- Worked on a fiscal and security risk analysis of the customs
administration and the investigation services project
- Maintained and extended a JEE/Spring based risk management
system with a JSF/PrimeFaces frontend and Oracle database
- Except for the daily business as bugfixing and different
requirements implementations this are the most interesting
parts on which i worked on:
◦ worked on the new powerful search architecture with
Elasticsearch involved
◦ migrated some EJB-Services to Spring
◦ migrated RIKO-Application from JBoss-EAP 7.4 to 8.0
together with Spring Boot from 2.7 to 3.3
- Supported developer and test colleagues
- Prepared Jenkins jobs
- Main used technics: JavaEE (JSF/PrimeFaces, EJB, JPA/Hibernate),
Spring Boot, REST-Services, Elasticsearch, Oracle DB,
Maven, Jenkins, Git, IntelliJ IDEA,
Oracle WebLogic JEE Server, JBoss-EAP