Senior COBOL & Java Modernization Engineer

About the Position

GFT is a pioneering company in digital transformation. We design business solutions focused on artificial intelligence (AI-Centric), modernize IT infrastructures, and develop next-generation core systems for leaders in the banking, insurance, and industrial sectors. In close collaboration with our clients, we challenge limits to help them achieve their full potential.

We are currently looking to incorporate a Senior COBOL & Java Modernization Engineer with proven experience in legacy system modernization environments, capable of analyzing mainframe applications, designing Java target architectures, and leveraging AI tools to accelerate technological transformation processes with guarantees of quality and functional equivalence.

Responsibilities

• Analyze COBOL programs and JCL spools to understand functional flows, dependencies, datasets, return codes, and existing business logic.
• Design and implement target solutions using Java, Spring Boot, and Spring Batch.
• Define jobs, steps, readers, writers, chunking processes, restart, and fault tolerance mechanisms.
• Develop and maintain functional and technical specifications under Spec-Driven Development approaches.
• Build and optimize agents, prompts, skills, and automations using AI tools for assisted development.
• Validate functional equivalence between legacy applications and new implementations.
• Design testing strategies, golden master, regression tests, and validation automation.
• Analyze quality, productivity, and efficiency metrics of the modernization pipeline.
• Identify opportunities for continuous improvement in processes, tools, and frameworks used.
• Collaborate closely with teams of experts in mainframe environments and enterprise architecture.

Requirements

• More than 5 years of professional experience in Java development.
• Professional level of English for documentation and international collaboration.
• Solid experience with:
  • Java
  • Spring Core
  • Spring Boot
  • Spring Data
  • Spring Batch in production environments
• Experience in high-volume batch applications and critical processes.
• Ability to analyze and understand existing COBOL and JCL code.
• Knowledge of:
  • Fixed-length files
  • Embedded SQL
  • Batch processing
  • Error handling and returns
  • Reprocessing and failure recovery
• Advanced testing experience:
  • Regression testing
  • Golden Master
  • Test case design
  • Mutation Testing
  • Code coverage
• Experience using AI applied to software development:
  • Prompt Engineering
  • Development agents
  • Evaluation of LLM outputs
  • Assisted code generation
  • Control of hallucinations and quality
• Regular use of:
  • Git
  • Bash
  • Python
  • Linux environments / Terminal

Nice to Have:

• Previous experience in banking and mainframe environments.
• Knowledge of:
  • z/OS
  • DB2
  • CICS
  • IMS
  • Control-M
• Participation in COBOL → Java migration projects.
• Experience with corporate batch frameworks in the financial sector.
• Experience building agent pipelines and advanced automations for development.
• Knowledge of methodologies based on executable specifications or Spec-Driven Development.
• Experience analyzing costs, token consumption, and quality metrics in AI-based solutions.

Personal Competencies

• We are looking for someone who:
  • Questions and validates code through objective tests and evidence.
  • Has a quality and continuous improvement mindset.
  • Is capable of understanding complex systems and documenting them clearly.
  • Enjoys solving highly complex technical problems.
  • Works collaboratively with multidisciplinary teams.
  • Knows how to listen, ask questions, and share knowledge with experts from different areas.
  • Maintains a vision oriented towards the sustainability and maintainability of solutions.
  • Is rigorous, analytical, and detail-oriented.

We Offer

• Work-life balance and flexibility: Possibility to work from home hybrid/remote, flexible schedules, and intensive Fridays.
• Training and Development: Personalized plan, training programs.
• Social Benefits: Life insurance, remote work support.
• Flexible Benefits "a la carte": Corporate voucher for food, transportation, health insurance, childcare, and training, tailored to your needs and combined with flexible compensation.
• Relocation Package (if applicable): Financial support, visa sponsorship advice.
• Referral Program.
• Wellness Program: Nutrition, physical, mental. Discounts with Wellhub. Free psychological support service.
• Life at GFT: Smart offices, events, values awards, inspirational talks.
• International corporate culture.

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Locations

• Alcobendas, M, ES, 28108
• Valencia, V, ES, 46002
• Lleida, ES, 25003
• Alicante, ES, 03010
• Sant Cugat del Vallès, B, ES, 08174

Work Location Type

• Remote / Hybrid

Join our global team!

As a partner for IT consulting and software development, we specialize in the digital transformation of our clients in the finance, insurance, and industrial sectors. Our approximately 700 talents in Germany develop sustainable solutions with the latest technologies.