Keystone Solutions
Senior Java Developer
Keystone SolutionsBelgium13 hours ago
Full-timeEngineering, Information Technology
Mission Overview:

Develop, program, test, and maintain assigned software applications and management software to deliver robust, scalable, and reliable IT solutions that meet current and future business needs. The role includes a strong contribution to the design and architecture of microservices solutions, with a specific focus on high availability, performance, scalability, and backward compatibility of versions.

Key Result Areas:

  • Participate in determining user needs and conduct feasibility analysis to understand business expectations, assess technical feasibility, and enable optimal implementation of solutions.
  • Perform technical analyses and draft documentation related to application developments and evolutions to ensure maintainability and scalability of solutions.
  • Design, develop, and maintain backend applications based on microservices architectures, ensuring overall system coherence.
  • Implement high availability, resilient, and high-performance solutions suitable for critical production environments.
  • Ensure version compatibility (backward compatibility) during application evolutions and deployments of new services.
  • Test developed solutions, ensure the quality of delivered code, and make necessary adjustments to meet quality standards and business needs.
  • Monitor developments in production, analyze incidents, and contribute to continuous improvement of applications.
  • Control, analyze, and resolve intervention requests and bugs to ensure reliable and stable application operation.
  • Act as a technical advisor for internal and external teams on both functional and technical aspects.


Responsibilities – Analysis and Expertise:

  • Understand and challenge client needs (what, why, who, when, where, how) with a critical, analytical, and creative mindset.
  • Master database modeling concepts and object-oriented programming.
  • Intervene across the entire backend technical stack.
  • Provide strong expertise in Java 21, including Reactive Streams, performance, and development best practices.
  • Design and implement microservices architectures (decoupling, inter-service communication, versioning, resilience).
  • Ensure architectural consistency of solutions and alignment with IT strategy.
  • Use and master associated frameworks and tools (Spring, Maven, Git, Jenkins, JIRA).
  • Document applications (technical documentation, processes, user manuals).


Responsibilities – Development and Testing:

  • Develop new features and fix bugs while respecting existing patterns and standards.
  • Implement testing strategies (unit and integration tests).
  • Review and test developments carried out by other team members.


Responsibilities – Support and Collaboration:

  • Support the business in the use of data and technical analyses.
  • Challenge business analyses with a technical perspective.
  • Actively participate in the team’s Agile way-of-life (SCRUM).
  • Respect the company’s IT governance and strategy.


Knowledge and Experience:

  • Master’s degree, Bachelor’s degree, or equivalent by experience.
  • Minimum 5 years of professional experience in backend analysis and development.
  • Proven experience in Java development (Spring, Reactive Streams).
  • Proven experience in the design and architecture of microservices, including:
    • High availability,
    • Versioning and backward compatibility management,
    • Performance and scalability.
  • Good knowledge of databases (Oracle, SQL, DB2).
  • Strong command of Git, Jenkins, and JIRA.
  • Knowledge of an IDE such as IntelliJ or equivalent.
  • Good knowledge of French or Dutch (spoken/written) and English (spoken/written).
  • Understanding spoken French is an asset (French-speaking team).

Desired Qualities:

  • Synthesizing mindset and strong organizational skills.
  • Proactivity and ability to propose improvements.
  • Autonomy and rigor.
  • Excellent communication and listening skills.
  • Ability for continuous learning (self-taught).
  • Team spirit and sense of responsibility.


Mission:

  • Working languages: FR / NL and EN
  • Team predominantly French-speaking


Role:

  • Senior Back-End Developer (most recent experience: this year)


Skills:

  • Agile – Expert
  • GIT – Expert
  • IntelliJ – Expert
  • Java – Expert
  • Jenkins – Expert
  • Jira – Expert
  • JSON – Intermediate
  • Maven – Expert
  • Reactive Programming – Expert
  • RESTful API – Expert
  • Soap API – Intermediate
  • Spring – Expert
  • SQL – Intermediate
  • WSDL – Intermediate
  • XML – Intermediate
  • XSD – Intermediate


Languages:

  • Dutch – Professional working proficiency
  • English – Full professional proficiency
  • French – Native or bilingual proficiency


Locations:

  • Main address: Place du Luxembourg, 2 E - 1420 Braine-l'Alleud
  • Other: Leuvensesteenweg, 639 - 3071 Kortenberg


Mission Overview:

This Senior Java Backend Developer / Software Engineer role is a consultancy mission delivered by Keystone Solutions for one of our clients. As a Keystone Solutions consultant, you will work closely with the client’s teams, primarily on-site at the client location, to design, develop, test, and maintain assigned software applications and management tools that provide robust, scalable, and reliable IT solutions meeting current and future business needs. The role includes a strong contribution to the design and architecture of microservices solutions, with a particular focus on high availability, performance, scalability, and backward compatibility across versions.

Key Result Areas:

As a Keystone Solutions consultant embedded with our client, you will carry out the following responsibilities:

  • Participate in defining user needs and perform feasibility analysis to understand business expectations, assess technical feasibility, and enable optimal solution implementation.
  • Conduct technical analyses and write documentation related to application developments and evolutions to ensure maintainability and scalability of solutions.
  • Design, develop, and maintain backend applications based on microservices architectures, ensuring overall system coherence.
  • Implement high-availability, resilient, and high-performance solutions suitable for critical production environments.
  • Guarantee inter-version compatibility (backward compatibility) during application evolutions and the deployment of new services.
  • Test developed solutions, ensure the quality of delivered code, and make necessary adjustments to meet quality standards and business needs.
  • Monitor developments in production, analyze incidents, and contribute to continuous improvement of applications.
  • Control, analyze, and resolve intervention requests and bugs to ensure reliable and stable application operations.
  • Act as a technical advisor for internal and external teams, both on functional and technical aspects.


Responsibilities – Analysis and Expertise:

  • Understand and challenge client needs (what, why, who, when, where, how) with a critical, analytical, and creative mindset.
  • Master database modeling concepts and object-oriented programming.
  • Contribute across the entire backend technical stack.
  • Provide strong expertise in Java 21, including Reactive Streams, performance, and development best practices.
  • Design and implement microservices architectures (decoupling, inter-service communication, versioning, resilience).
  • Ensure architectural coherence of solutions and alignment with IT strategy.
  • Use and master associated frameworks and tools (Spring, Maven, Git, Jenkins, JIRA).
  • Document applications (technical documentation, processes, user manuals).


Responsibilities – Development and Testing:

  • Develop new features and fix bugs while respecting existing patterns and standards.
  • Implement testing strategies (unit and integration tests).
  • Review and test developments delivered by other team members.


Responsibilities – Support and Collaboration:

  • Support the business in data usage and technical analyses.
  • Challenge business analyses with a technical perspective.
  • Actively participate in the team’s Agile way of life (SCRUM).
  • Respect the company’s IT governance and strategy.


Knowledge and Experience:

  • Master’s, Bachelor’s, or equivalent by experience.
  • Minimum 5+ years of professional experience in backend analysis and development.
  • Proven experience in Java development (Spring, Reactive Streams).
  • Proven experience in the design and architecture of microservices, including:
    • High availability,
    • Versioning and backward compatibility,
    • Performance and scalability.
  • Good knowledge of databases (Oracle, SQL, DB2, and related technologies).
  • Strong command of Git, Jenkins, and JIRA.
  • Knowledge of an IDE such as IntelliJ or equivalent.
  • Good knowledge of French or Dutch (spoken/written) and English (spoken/written).
  • Oral comprehension of French is an asset (French-speaking team).

Desired Qualities:

  • Ability to synthesize and strong organizational skills.
  • Proactivity and a strong sense of initiative.
  • Autonomy and rigor.
  • Excellent communication and active listening.
  • Capacity for continuous learning (self-taught).
  • Team spirit and strong sense of responsibility.


Mission Details:

  • Working languages: FR / NL and EN.
  • Team predominantly French-speaking.


Consultancy Model at Keystone Solutions:

As a Keystone Solutions consultant, you will work primarily on-site at our client’s location, collaborating daily with stakeholders to design, build, and evolve production-grade microservices platforms. You remain a full member of Keystone Solutions, benefiting from our community, coaching, and knowledge-sharing culture while delivering impact within the client’s environment.

Dynamic Projects Across Clients:

  • Tackle diverse challenges spanning microservices design, high availability, performance tuning, and versioning strategies across different industries and contexts.
  • Leverage proven engineering practices from Keystone Solutions to accelerate delivery while adapting to each client’s architecture and governance.
  • Build reusable patterns that strengthen both the client’s ecosystem and Keystone Solutions’ shared knowledge base.


Turbo-Charged Learning and Development:

  • Access continuous learning through coaching, peer reviews, and internal guilds focused on Java 21, Reactive Streams, Spring, and cloud-native architectures.
  • Benefit from personalized development plans, certifications support, and regular feedback cycles to refine your craftsmanship.
  • Showcase your expertise through brown-bag sessions, reusable templates, and best-practice playbooks across engagements.


Ambition Skyrocketing within a Consultancy Framework:

  • Grow your responsibility rapidly by owning critical backend components, leading design reviews, and mentoring teammates on client engagements.
  • Shape solution roadmaps with architecture stakeholders while aligning with enterprise strategy and long-term maintainability.
  • Advance your career through varied missions that broaden your technical breadth and deepen your architectural expertise.


Keystone Solutions’ Values in Action:

Being a K-Stone means bringing excellence, integrity, curiosity, and collaboration to every client project. We deliver pragmatic solutions, communicate transparently, share knowledge generously, and take ownership from design through production operations—ensuring measurable business impact and sustainable engineering quality.

Role-Specific Impact as a Consultant:

In this Senior Java Backend mission, you will apply Java 21, Reactive Streams, and Spring to architect and implement resilient microservices that meet strict SLAs. You will ensure backward compatibility across service versions, optimize database interactions (Oracle, SQL, DB2), industrialize delivery with Git, Jenkins, and JIRA, and champion Agile practices—adapting patterns to each client’s constraints while upholding Keystone Solutions’ engineering standards.

How to Apply:

If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal.

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