Lead Java Engineer

About the role

As a Lead Java Engineer, you will design and build the back-end services behind business-critical applications at our Client, a European public sector organization working in the area of competition policy. You will take technical ownership of business logic, APIs, and data access — across Java and Spring services, SOAP and REST interfaces, Elasticsearch for search, and Kafka for event streaming — and act as the technical reference point for the team. The role may involve access to sensitive non-classified or EU Classified Information, so discretion and adherence to security rules are part of the everyday work.

Responsibilities

• Design, develop, and maintain back-end services and business logic in Java and the Spring Framework, including the data access beneath them
• Take technical ownership of the services you deliver, including their correctness, error handling, performance, and security in production
• Provide technical leadership to the team — reviewing code, sharing knowledge, taking part in multilingual discussions with stakeholders, and turning requirements into workable technical solutions
• Design, build, secure, and document SOAP and RESTful web services, including OpenAPI/Swagger documentation and authentication and authorization mechanisms
• Design and optimize relational and document data structures, writing complex SQL queries and weighing consistency against performance
• Implement and maintain search capability with Elasticsearch, covering data indexing, search optimization, query design, and performance monitoring
• Build event-driven integrations with Apache Kafka, including message brokering, topic management, and integration within distributed system architectures
• Analyze complex back-end issues using APM and observability tooling, identify root causes, design effective solutions, and keep technical documentation current

Requirements

• A university degree at master's level (or 5 years of higher education) with a minimum of 15 years of IT professional experience
• Minimum 15 years of experience in software development and minimum 15 years developing Java applications, with proficiency in back-end languages (Java, PHP) and frameworks (Spring Boot, Hibernate, Node.js) and a strong understanding of the web development cycle and programming techniques and tools
• Minimum 15 years of experience with the Spring Framework
• Minimum 10 years of experience with SOAP Web Services and minimum 5 years with REST API development, including designing, building and securing RESTful APIs and web services with OpenAPI/Swagger documentation, and understanding of authentication and authorization standards (e.g. OAuth 2.0, OpenID Connect, JWT)
• Minimum 3 years of experience with Elasticsearch, including data indexing, search optimization, query design and performance monitoring, and minimum 3 years with Apache Kafka for event streaming, message brokering, topic management, and integration within distributed system architectures
• Experience with SQL databases, including relational databases such as PostgreSQL, Oracle and MySQL with complex SQL queries and database design, together with knowledge of NoSQL document stores (MongoDB, CouchDB, CosmosDB) and the consistency and performance trade-offs involved
• Experience working in Agile environments, with Git workflows (GitFlow, trunk-based) and an understanding of legacy systems using SVN, containerization and orchestration technologies (Docker, Kubernetes), APM tools (Dynatrace, Splunk, Elastic APM) and OpenTelemetry for metrics, logs and traces, Case Management tools including workflow configuration, case lifecycle handling, user support and process optimization, and professional experience in the area of competition policy. An optional certification — AWS Certified Developer Associate, Microsoft Azure Developer Associate, CNCF Certified Kubernetes Application Developer (CKAD), or equivalent — is welcome
• Eligibility for a personal security clearance at national level equivalent to EUCI SECRET UE/EU SECRET, as the role may involve access to sensitive non-classified (SNC) information or EU Classified Information, handled in line with Commission Decisions 2015/443 and 2015/444 of 13 March 2015
• Very good knowledge of English, both spoken and written, corresponding to Level B2 or higher (CEFR), with French as an additional asset, together with attention to detail in code correctness, error handling and documentation, the ability to analyze complex back-end issues and design effective solutions, excellent interpersonal and communication skills, integration into an international and multicultural environment, participation in multilingual meetings, and the ability to work both autonomously and as part of a team with a results-oriented mindset