Legacy and Mainframe Code Conversion using GitHub Copilot

Capgemini Group

A Generative AI powered approach to modernizing legacy mainframe applications by automating code extraction, UI/API generation, and test case development using GitHub Copilot.

Capgemini’s Mainframe Code Conversion Journey enables organizations to modernize legacy mainframe applications by leveraging GitHub Copilot for:

  1. Extracting business rules from mainframe code ~40% faster than traditional approaches.
  2. Generating UI (ReactJS) and API (Spring Boot) code, even for developers with no prior knowledge, reducing development effort by 70%.
  3. Automating unit test case creation, achieving 90% automated test coverage for APIs.
  4. Reducing SME dependency by 50%, as GenAI clarifies routine business rules with minimal manual intervention.
  5. Enhancing DevOps automation through GitHub Copilot-generated OpenAPI specs, build scripts, and deployment pipelines.

This solution drives increased adoption of Microsoft products such as:

• Azure DevOps & GitHub – Integrated CI/CD for mainframe-to-cloud transformation.

• Microsoft Excel – Exporting legacy system insights for analysis.

• VS Code – Optimized GenAI-driven development with Copilot integration.

Project Deliverables:

• Automated Code Extraction from COBOL, JCL, Copybooks using GitHub Copilot.

• GenAI-driven UI & API Code Generation with ReactJS (UI) and Spring Boot (API).

• Automated Unit Test Case Generation (~90% test coverage).

• Code Refactoring & Consolidation for efficient modernization.

• DevOps Automation via OpenAPI specs, build scripts, and containerization.

• Legacy System Analysis & Documentation using AI-assisted prompts.

Duration:

Ongoing implementation with the ability to scale based on enterprise modernization needs.

Technologies Involved:

• GitHub Copilot

• Microsoft Azure DevOps

• ReactJS & Spring Boot

https://store-images.s-microsoft.com/image/apps.34126.5005e9ee-6979-4fbd-8929-da2504fad8a2.1c5428df-182b-4291-a5b6-bd813a7d2463.2583e43c-df7e-4271-8f3f-fa9a6052f93d
https://store-images.s-microsoft.com/image/apps.34126.5005e9ee-6979-4fbd-8929-da2504fad8a2.1c5428df-182b-4291-a5b6-bd813a7d2463.2583e43c-df7e-4271-8f3f-fa9a6052f93d
https://store-images.s-microsoft.com/image/apps.14924.5005e9ee-6979-4fbd-8929-da2504fad8a2.1c5428df-182b-4291-a5b6-bd813a7d2463.2074654b-28dd-41fe-9937-61ac29500dbd
https://store-images.s-microsoft.com/image/apps.2702.5005e9ee-6979-4fbd-8929-da2504fad8a2.67febe2d-d5d8-4f27-9282-a72561037d68.cbea9cef-ecee-48e3-8771-38e50b288ef4