27.10.2026 aktualisiert
verifiziert
Premiumkunde
100 % verfügbarSenior Java Developer / Consultant
Zabok, Kroatien
Deutschland +2
Ms.Sc. Computer Science (diploma engineer), Faculty of Electrical Engineering and Computing, Zagrebinfo: Deutschland, Österreich, Schweiz
Über mich
Experienced Java/Spring software engineer and tech lead (18+ years). I lead technical initiatives and contribute individualy. Had roles in design, development, deployment, testing and optimization in many projects from various industries like Fintech, Telecom, Energy, Banking, Government, etc.
Skills
Web InterfacesJavaXml-SchemaSpring SecurityApache ActivemqApache TomcatCode-ReviewDatenbankenContinuous IntegrationDB2 SQLSoftware Design PatternsLinuxGradleGrailsHibernate
Languages & Runtimes: Java (J2SE 1.4 / 1.5 → Java 21 / 25), Kotlin, Groovy, SQL, JavaScript, Scala
Frameworks: Spring Boot 3 / 4, Spring Security, Spring Data JPA, Spring Cloud Gateway, WebFlux, Hibernate, Java EE / EJB, Camunda BPM, Apache CXF, Grails, Axon
Architecture: Microservices, Multi-tenancy, Domain-Driven Design, Event-Driven Architecture, SOA, REST, OpenAPI / contract-first, RFC 9457, Design Patterns, UML, Data Modeling
Security & Identity: Keycloak (incl. custom SPI extensions), OAuth2 / OIDC / JWT, RBAC, PKI / X.509, EJBCA, Certificate Transparency, eIDAS, TLS / SSL, SmartCard PKI
Cloud & Infrastructure: AWS (ECS Fargate, ALB, SQS, S3, WAF, CloudFormation), OpenShift, Kubernetes, Docker, WebSphere Liberty / AS, Tomcat, Jetty, JBoss, Linux
Data & Messaging: MySQL, PostgreSQL, Oracle, IBM DB2, MongoDB, Redis, Caffeine, HikariCP, Apache Kafka, ActiveMQ / JMS, IBM WebSphere MQ
Quality & Delivery: Testcontainers, JUnit, Spock, ArchUnit, SonarQube, MapStruct, OpenTelemetry, JFR / async-profiler, GitLab CI, Jenkins, Maven, Gradle, Git
AI-assisted Engineering: Claude Code (custom skills & subagents), MCP integrations, LLM API integration, prompt engineering, machine-readable engineering standards
Leadership: Technical leadership, architecture ownership, code review, mentoring, refinement & technical grooming, stakeholder communication
Erfahrung
Berufserfahrungmehr als 10 Jahre
Freelancer seit2016
Sprachen
GermanGrundkenntnisseEnglishverhandlungssicherCroatianMuttersprache
Projekthistorie
Greenfield rebuild of a legacy Delphi pediatric EHR into a multi-tenant Spring Boot microservice platform on AWS, coexisting in production with the legacy desktop client. Backend technical lead: designed and built the shared platform library every service inherits - database-per-tenant routing with lazy and cached connection, JWT resource-server security with RBAC derived from the legacy permission catalog, tenant-local datetime handling, legacy-compatible audit trail, event publishing for desktop coexistence, RFC 9457 problem details, safe pagination/sort parsing and deadlock-resilience primitives. Bootstrapped domain services from a common contract-first template. Built the Kotlin BFF/gateway authentication and session layer (Keycloak multi-realm, single active session, inactivity timeout with heartbeat, SSE pass-through, multi-location login) and a Keycloak Event Listener SPI. Root-caused and fixed intermittent production MySQL deadlocks and turned the fix into a fleet-wide prevention standard; enforced architecture as ArchUnit tests and acceptance-criteria e2e suites. AI-assisted engineering: runs day-to-day delivery through Claude, with the project’s engineering standards and the ticket lifecycle itself written down as machine-readable rules and custom skills - refinement verified against legacy sources, implementation in vertical slices delegated to specialised subagents. Ticket refinement and technical grooming, technical sign-off reviews, code review and mentoring.
Implementation of new Croatian Automated Import System (CCI – centralised customs) project for Croatian Customs. Technical leadership, proof-of-concept solutions, integration with external system, Implementation of integration modules for CCN2 (EU inter-member-state message exchange) and bookkeeping system (NIK), code review, mentoring, supported developers. Implemented also integration with Tariff system, implementation of national rules validation modules, implementation of various business process use-cases. Support DevOps and testers.
Built a custom SOAP API Gateway with security transformation & termination features for government customs administration. I was sole designer & developer of a PoC and, after evaluation, the full-featured solution. Refactored the solution to support OpenShift deploment, application deployment containerization and configuration simplification.