Jean Claude Mbeng

Jean Claude MBENG Senior Java Spring Boot Developer Email :-Phone : +33 - Adress : Chaussée d’Asie 57100 Thionville LinkedIn : https://www.linkedin.com/in/jean-claude-mbeng Passionate about web and IT technologies, senior developer specialized in Java (Spring Boot) and with Angular front end skills, solid experience in developing high-performance microservices applications with Spring Cloud, integrating Kafka, and CI/CD automation via Azure DevOps / GitLab. Solid experience in backend application modernization and Agile (Spotify model) / (SCRUM) environments. Java Spring Boot Microservices Angular Kafka Technical skills Languages Java 8,17,21, JavaScript, TypeScript Framework et libraries Spring Boot 2 & 3, Spring Security, Spring Data JPA,Spring Bach, Spring Cloud, Hibernate, Lombok, Angular Databases & tools SQL Server, Oracle, PostgreSQL , MySQL, MongoDB,Cassandra Operating systems Windows , Linux (RedHat), Testsing and quality tools JUnit 5, MockMvc, Mockito , TestContainers , SonarLint, SonarQube Methods and standards SOLID, MVC, Software craftsmanship , Clean Code, TDD, DDD, Design Pattern Project management & tools Agile Scrum , Spotify Model,Safe, JIRA, Azure Board, Confluence DevOps, Versionning Docker, Azure DevOps, Maven Tool ELK Stack (Elasticsearch, Logstash, Kibana), Prometheus, Grafana, Redis, Kafka, Git, Jenkins Training & Certification 2024 (On going) MASTER 1 – MIAGE Université d’Amiens 2023 Udemy Training : Apache Kafka for Developers using Spring Boot https://ude.my/UC-20f2ba14-744b-478a-bade-f51ec8a0c3a7/ 2023 Udemy Training : Learn Spring Boot 3 in 100 Steps - No 1 Java Framework https://ude.my/UC-4eeb9b3f-b-e31-9e8a-/ 2012 BSC IT Security Institut du Management et de L’entrepreneuriat - Douala. 2010 BTS Applied programming for the Internet Institut Supérieur des Technologies et du Design Industriel - Douala Languages French Native Anglais Professionnal (B2 / C1) Projects & Work experience SENIOR JAVA CONSULTANT (Since 03/2025) Projet : Migrating business applications from Java 8 to Java 21 Context : Modernization of the Wholesale Banking ING backend business applications composed of several critical services written in Java 8 and based on JAX-RS (Jersey), in a monolithic architecture evolving towards microservice applications written in Java 21 and based on Spring Boot. Working Methodology: Agile Spotify Key achievements and responsibilities : Backend development Migration applicatiion from Java 8 to Java 21 :  Impact analysis of version changes (deprecated APIs, JVM changes, etc.)Analyse d’impact des changements de version (deprecated APIs, changements JVM, etc.)  Gradual refactoring of the code to take advantage of new features:  Improving the readability, performance and maintainability of the code. Refactoring of REST APIs from JAX-RS (Jersey) to Spring Boot :  Implementation of REST controllers via Spring Web and standardisation of exception handling with @ControllerAdvice Replacement of Jersey-specific annotations with Spring Boot conventions (@RestController, @RequestMapping, etc.)  Migration of authentication filters to Spring Security with integration of JWT. Setting up and automating CI/CD with Azure DevOps :     Création et maintenance des pipelines YAML dans Azure DevOps pour les builds Maven, les tests automatisés (JUnit, Mockito). Déploiement automatisé vers des environnements de recette et préproduction via Azure Pipelines. Suivi des métriques et alerting via Zabbix. Other technical contributions :  Integration of Spring Boot Actuator to expose application metrics Implementation of non-regression tests to secure refactorings and migrations  Active participation in code reviews, daily stand-ups and customer demos within an Agile framework (Spotify) Results obtained :     40% reduction in technical debt on core modules ~20% improvement in backend performance thanks to Java 21 and the use of virtual threads Increased reliability of deployments with enhanced test coverage and robust DevOps pipelines Technical environment : Frameworks& Languages : Java 8 , 11, 21, Spring Boot, Jax-RS, Jersey, Spring Security , Spring Batch, Databasess : DB2; Azure DevOps , Linux Redhat, Docker, Kafka SENIOR JAVA DEVELOPER (02/2024 – 03/2025) Client / Project : European Commission / RADD EuroAtom – RADD Role: (Java Backend Tech Lead / Angular Front-end Developer) Technical Lead on RADD, a database maintained by the European Commission for the collection of information on radioactive effluent discharges. The aim of the project was to modernise the application in order to improve its performance, security and accessibility. Equipe : 1 Projet Director, 2 Project Manager, 2 Dev senior ( 1 Tech Lead), 3 Juniors Working methodology:- Agile Scrum Key achievements and responsibilities : Architecture and Conception    Design and implementation using Spring Boot and advanced concepts such as Domain-Driven Design (DDD). Implementation of Design Patterns to solve complex problems (Singleton, Factory, Builder, etc.). Definition of the RESTful architecture for the APIs, in compliance with the HATEOAS principles and the OpenAPI contract (Swagger).  Définition de l’achitechture micro-services avec intégration de Spring Cloud / Api Gateway Backend development         Developing robust and scalable backend APIs using Spring Core, Spring Data JPA, Spring Security and Spring Web. Creation and management of complex relationships with Hibernate and JPA for the Oracle database. Developing REST Json end points. Setting up a pagination system, filter use criteria, and JPA Specification. Writing specific SQL queries using JPA / Hibernate and JPQLFrontend development Conception et développement de composants réactifs en Angular pour une application web dynamique. Intégration des APIs RESTful en utilisant RxJS pour gérer les flux de données. Setting up complex forms with personalised validation. Performance and scalability   Optimising API performance with techniques such as caching (Spring Cache) and advanced thread management. Implementation of scalability mechanisms (Load Balancing, Rate Limiting). Security  Integration of the European Commission's EU-Login SSO system Advanced Spring Security configuration: role-based authentication and authorisation, OAuth2, and User Token management.  Implementation of OWASP-compliant security strategies to prevent vulnerabilities (XSS, CSRF, SQL Injection). Testing and Code Quality   Writing unit and integration tests with JUnit, Mockito, and TestContainers. Using the Spring Test framework to test service layers.  Monitoring and improving code quality with tools such as SonarQube and SonarLint. DevOps and Deployment   Deploying Spring Boot in cloud environments (AWS, Kubernetes/Docker). Automating builds and deployment with CI/CD (GitLab CI). Technica leadership   Mentoring junior/mid-level developers, code review to ensure compliance with best practice. Active participation in key technical project decisions and priority setting.  Leading peer programming sessions and internal training on advanced topics (architecture, frameworks). Agile Collaboration  Participating in Agile ceremonies: Stand Up, Sprint Reviews and Retrospectives.  Interaction with business teams to gather requirements and define technical user stories.  Technical environment: Languages & Frameworks: Java 17, Spring Boot 3, Spring Security; Frontend : Angular; Database: Oracle; Containerisation: Docker; Orchestration: Kubernetes; Cloud: Spring Cloud, Api Gateway , AWS; Operating systems: Linux; Scripting tools: Bash; Authentication: EULogin Client / Project : Government of Luxembourg (Ministry of Agriculture) / MA-PRIME Role : Tech Lead Java EE Technical Leader on the MA.PRIME project, aimed at calculating and paying premiums for farmers under the Common Agricultural Policy (CAP). This project is helping to automate and optimise the processes for allocating agricultural subsidies in Luxembourg. Team : 1 PM, 1 Senior Developer (Tech Lead), 2 Juniors Working methodology: Agile / Scrum Key achievements and responsibilities : Architecture and Conception  Setting up the development enviroment using the compile image of the CTIE Design and implementation using EJB.  Implementation of Design Patterns to solve complex problems (Singleton, Factory, etc.).  Definition of the RESTful architecture for the APIs Backend development  Developing robust and scalable backend APIs using EJB and Jersey.  Writting DAO layer for the database acces using EclipseLink for IBM DB2  Developing REST Json end points.  Setting up a pagination system, filter use criteria, and JPA Specification.  Performance and scalability  Implementation of scalability mechanisms (Load Balancing, Rate Limiting). Testing and Code Quality  Writing unit and integration tests with JUnit5 Monitoring and improving code quality with tools such as SonarQube and SonarLint. DevOps and Deployment   Deploying application using Gitlab pipeline Automating builds and deployment with CI/CD (GitLab CI). Technical leadership   Mentoring junior/mid-level developers, code review to ensure compliance with best practice. Active participation in key technical project decisions and priority setting.  Leading peer programming sessions and internal training on advanced topics (architecture, frameworks). Agile Collaboration  Participating in Agile ceremonies: Stand Up, Sprint Reviews and Retrospectives.  Interaction with business teams to gather requirements and define technical tasks.  Environnement technique : Java 8, EJB, EclipseLink JPA , API : REST, JSON, IBM DB2, Design patterns : Strategy, Singleton, Factory, Méthodologies : Test Driven Development (TDD), principes SOLID SENIOR SOFTWARE DEVELOPER (10/2023 - 02/2024) Client / Project : Stellantis / Performance and security audit of the LIVEPR application Role : Auditor - Java Developer Taking part in an audit of the LIVEPR application, used to control the carrier robots at the Stellantis site in Vesoul. The project focuses on analysing the system's performance and safety, with the aim of improving the management of robots in logistics operations. Team : 1 PM, 3 Dév seniors Working methodology: Agile / Scrum Key achievements and responsibilities : As auditor :        In-depth performance analysis and security audit of the LIVEPR application. Drafting of detailed audit reports including test results and suggestions for improvement. Proposing solutions to enhance the stability, security and performance of the system. Contribution to the design and development of the technical architecture. Implementation of patches and optimisations. Use of good development practices such as TDD and SOLID principles. Collaboration with development teams to integrate suggested improvements. Technical environment: Systèmes d'exploitation : SUSE, Linux, Solaris ; Langages & Frameworks : Java 1.6, Java 1.5, Spring, EclipseLink JPA ; Base de données : Oracle ; Outils : Maven, Citrix, JProfiler, JMeter ; Méthodologies : Test Driven Development (TDD), principes SOLID BACKEND JAVA DEVELOPER (03/2023 - 08/2024) Client / Project : RATP / Audit of an ETL Rôle : Auditor - Java Developer Technical audit of the inter-application data exchange platform on behalf of RATP. Team : 1 PM, 1 Tech Lead, 1 DevOps, 2 dév seniors Working methodology: Agile / Scrum Key achievements and responsibilities : As auditor :  :Analysis of ITE application performance and identification of bottlenecks. Suggested improvements to optimise the speed and efficiency of data exchanges.  Drafting of detailed audit reports with technical recommendations.  Peer programming  Development and implementation of patches to improve application performance.  Collaboration with technical teams to integrate suggested improvements.  Using Bash on Linux to automate maintenance tasks and performance tests. Technical environment: Bash, Linux, JAVA 8, Spring, ActiveMQ, PostgreSQL, Maven  JAVA TECHNICAL REFERENT - JAVA BACKEND DEVELOPER (07/2017 - 03/2023) Project : Managing the migration of the UNI-SCHOOL School ERP from a monolith to a micro-service architecture Role : Tech Lead Java Team : 1 PM/Scrum Master, 1 Tech lead, 1 DevOps, 2 Dév seniors, 2 dév juniors, 1 testeur Working methodology: Agile / Scrum Key achievements and responsibilities : Analysis and documentation :  Analysis of the monolithic architecture: I worked with the team to understand the existing architecture of the monolithic application, how it worked and its dependencies. We identified the services and functionalities to be broken down into microservices.  Define the data formats to be used for communication between microservices.  Analyse the impact in terms of costs and workload associated with the migration.  Draft the detailed functional specifications (DFS) for each microservice identified.  Model the database for the various microservices using SQL Server Management Studio. Architecture & Conception:  Contributing to the definition of the technologies (Framework, libraries and languages) to be used, in close collaboration with the Project Architect such as Spring Cloud with Spring Cloud Gateway .  Define the appropriate inter-microservices communication model (REST, Json).  Set up the microservices architecture using Spring Cloud  API Gateway  Eureka (Service Discovery)  Config Server for outsourced configuration  ZIPKIN for metrics  Swagger / Open Api for API documentation description Development:      Integrate payment APIs: Stripe API for card payments, Orange Money and MTN Mobile for mobile payments Develop server-side functionality to manage requests and responses related to payments Create endpoints for Stripe and Mobile Money API calls to manage payment events. Implement logic to manage payment transactions, including charge creation, subscription management, refund, coupon and discount management... Developing data access modules with Spring Data JPA, Hibernate, and writting specifics SQL with JPQL for complex queries Secutity :    Securing endpoints with KeyCloak Integrate Keycloak with the application to manage authentication, authorisation and user session management. Integration of an OPT system using SMS to authenticate each connexion after a certain time Performance and scalability           Designed and developed microservices architecture using Spring Cloud (Eureka, Config, Gateway) Implemented load balancing and service discovery with Eureka Integrated circuit breakers and retry mechanisms using Resilience4j for fault tolerance Used Kafka for asynchronous communication to improve scalability and decoupling Externalized configuration with Spring Cloud Config Server for dynamic, scalable deployments Enabled horizontal scaling and container orchestration with Docker and Kubernetes Applied caching strategies (Redis) and database optimization for high-performance data access Conducted load testing with JMeter to simulate high traffic and tune performance Monitored services using Prometheus, Grafana, and centralized logs with ELK Stack (Elasticsearch, Logstash, Kibana) Achieved 99.99% uptime and supported tens of thousands of concurrent users Testing and Code Quality :  Implementing the SOLID and Software craftsmanship principles Increasing the coverage of automated tests using the TDD approach to reach up to 90% of the code covered by unit tests.  Conduct an in-depth analysis of the application's functional and technical requirements in order to determine the priority characteristics for test automation.  Use automated test tools such as JUnit 5, MockMVC, Mockito and others to create and run automated test scripts.  Clearly and accurately documenting automated test cases, results and problems identified.  Participating in the implementation of CI/CD pipelines incorporating automatic validation stages via tests.  Practising TDD during the development of critical components. Technical leadership     Mentoring junior/mid-level developers, code review to ensure compliance with the best practices. Active participation in key technical project decisions and priority setting. Leading peer programming sessions and internal training on advanced topics (architecture, frameworks). Technical environment : JAVA 11, Spring Boot 2.6, Spring Data, JPA, Stripe, Rest , Swagger, Lombok, Spring Security, KeyCloak, JUnit5, Postman, SQLServer, Gitlab, JUnit, Stripe Api, Orange Money Web Api, Maven, Git, Jenkins, SQL Server Management Studio, Spring Cloud Project : UNI SCHOOL Role : Senior Java Developer Team : 1 PM/Scrum Master, 1 Architecte / Tech lead, 4 dév (1 senior et 3 juniors) , 2 testeurs Working methodology: Agile / Scrum Key achievements and responsibilities : Analysis and documentation :  Identify and list the business functions to be developed in the ERP  Gather requirements from end-users in partner schools.  Draft the specifications  Draft the general functional specifications (GFS) for each business area identified.  Define the target architecture of the ERP (Framework, languages to be used and target databases)  Write the guides (Administrator, User, Maintenance) Architecture & Conception:          Participated in the design and development of the UNI SCHOOL ERP as a modular monolithic application using Java 8 and Spring Boot Defined clear layered architecture: Controller, Service, Repository, and Entity (Domain) layers following SOLID principles Structured the application into functional modules (Student, Teacher, Course, Grades, Timetable, Finance, Authentication, Administration) to ensure separation of concerns Implemented role-based access control (RBAC) and JWT-based authentication/authorization Designed relational data models and entity relationships using JPA and Hibernate Managed RESTful API design for external system integration (e.g., payment providers, SMS/email APIs) Optimized performance with caching (Spring Cache + Ehcache) and connection pooling (HikariCP) Applied centralized exception handling, validation, and logging using Spring AOP Collaborated with the team to document and enforce code quality standards and naming conventions  Development :  Create user interfaces and administration screens (HTML, Thymeleaf) Develop ERP business layer services  Set up a dual authentication system (Login/Password + SMS OTP via Twilio)  Developing the data access layer with JPA + Hibernate  Versioning developments using SVN  Install and configure the WebLogic application server  Train the end usersDraw up the acceptance specifications.  Provide post-production support and correct any anomalies. Technical environment : Java 8, Spring Boot 2.6, MySQl 8, SVN Server, Turtoise SVN, Data At Rest, JUnit, Twilio SMS , MySQL Workbench  JAVA BACKEND DEVELOPER (02/2015 - 06/2017) Projet : e-Wallet MTN MoMo Mobile Money Online Link : https://momodeveloper.mtn.com/ e-Wallet MTN MoMo (Mobile Money) is an electronic wallet solution developed to facilitate financial transactions via mobile. This application allows users to manage their money securely, make payments, money transfers, online purchases and pay bills directly from their mobile phone. Role : Java Developer Team : 2 PM / Scrum Master, 1 Architecte/Tech lead, 1 DBA, 1 Ing. System, 8 Dev (2 seniors +6 Junior), 2 testers Working methodology: Agile / Scrum Key achievements and responsibilities : Analysis and documentation :  Participate in Agile ceremonies:  Develop my communication and collaboration skills, particularly in an Agile environment, with an emphasis on team self-organisation and adapting to change.  Write the specifications based on the business users' expression of need.  Drawing up the specification files (functional and technical).  Drafting the Administrator and Maintenance guides. Conception:  Assisting the project architect in defining technologies (framework, libraries and languages, type of infrastructure). Development :  Contributed to the development of the MTN MoMo Online payment system using Java 8 and Spring Boot  Designed and implemented secure RESTful endpoints for core operations: RequestPayment, DoRefund, Deposit, and BalanceCheck  Integrated with MTN Mobile Money APIs, managing authentication, encryption, and secure callbacks  Developed transaction handling logic including idempotency checks, status tracking, and error recovery  Utilized JPA/Hibernate for data persistence, ensuring consistency in all financial transactions  Applied Spring Security for API token validation and endpoint protection     Ensured auditability and traceability by implementing detailed logging for each operation (RequestPayment, DoRefund, Deposit) Wrote unit and integration tests using JUnit and Mockito to ensure stability of the payment processes Collaborated with cross-functional teams (front-end, mobile, QA) to ensure seamless API integration and user experience Participated in debugging and resolving production issues to maintain high system availability and accuracy Technical environment : Java 8, Spring Boot, Spring Data JPA, Hibernate, Spring Security, Passay, JavaScript, JQuery, Thyemleaf, Ajax, Weblogic, Redhat Linux Server, Oracle 12c, SVN, Turtoise, Oracle SQL Developer, MS Project PHP DEVELOPER (07/2013 - 01/2015) Project : EBANO Finance Design and development of a platform to put European investors in touch with companies in Africa.Lien : https://www.ebanofinance.com/ Role : PHP / HTML Developer Team : 1 PM/Scrum Master, 1 dév. senior/Tech lead, 1 dév junior, 1 testeur Working methodology: Agile / Scrum Key achievements and responsibilities : Analysis and documentation :  Draft a first version of the specifications under the supervision of the Tech lead  Validate the specifications with the PO  Write the administrator guide and installation guideConception:  Modelling the database with MySQL Workbench and producing a MCD Development :      Develop the business modules on CodeIgniter 2.4 Integrate the Stripe API into the card payment module Develop the activity reports on the administration space using Jquery 2.0 and Ajax Deploy the platform on shared hosting Configuring Cron for Google Finance on CPanel to update exchange rates Technical environment : CodeIgniter 2, Google Finance, Jquery 2.0, Ajax, Stripe, CPanel, CronTab, METRONIC Dashboard 4, Active Records, Query Builder, MySQL Workbench, MySQL, HTML, CSS