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# Senior Java Software Developer

- **Company:** ALTEN
- **Location:** Brussel, Belgium (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Java (Programming Language), Apache Tomcat, Server Applications, Continuous Integration, Middleware, OpenShift, Java Application Server, Enterprise Software Applications, Spring-boot, Containerization, Kubernetes, Code Restructuring
- **Published:** September 6, 2026
- **Apply:** https://www.adzuna.be/details/5872063390

## About the Role

* You have at least 5 years of experience in Java, spring or spring boot
 * You have strong experience in Java development with expertise ranging from Java 7 to Java 21+.
 * You have proven experience in large-scale Java Upgrade & Migration projects.
 * You have expert-level knowledge of Java Core and enterprise application development.
 * You have strong analytical skills with extensive experience in troubleshooting and resolving complex technical issues.
 * You are able to assess legacy architectures and define modernization roadmaps.
 * You have experience with application servers and middleware technologies.
 * You have hands-on experience with Tomcat.
 * Experience with OpenShift, Kubernetes and containerized environments is considered a strong asset.
 * Good understanding of CI/CD and modern deployment practices.
 * Strong communication and collaboration skills.
 * Professional proficiency in Dutch or French, combined with good English.

## Description

As part of our ongoing growth, we are looking for a Senior Java Software Developer to join our teams and work on client projects located in Brussels. You will join our client's application modernization initiative, focused on upgrading and modernizing a portfolio of existing Java applications running on legacy environments.

As a Senior Java Upgrade & Migration Engineer, your main responsibilities will include:

 * Analyze existing Java applications running on legacy Java versions (starting from Java 7).
 * Plan and execute migrations towards modern Java versions (Java 17, 21 and above).
 * Identify and resolve compatibility issues related to frameworks, libraries, and application servers.
 * Perform code refactoring and modernization to comply with current Java best practices.
 * Troubleshoot and resolve complex technical issues during migration activities.
 * Conduct impact assessments and define migration strategies for legacy applications.
 * Collaborate with development teams, architects, and infrastructure experts throughout the upgrade process.
 * Support testing, validation, and deployment of upgraded applications.
 * Contribute to the modernization of application hosting environments.
 * For part of the team, support containerization and deployment activities using OpenShift, Kubernetes, and Tomcat


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