COBOL Job Analysis and Business Logic Extraction - Individual Record Matching

STATUS

COMPLETED

TIMELINE

Started: 2025-12-15
Completed: 2025-12-16

TECHNOLOGIES

COBOLDB2JavaSpring Boot

Postmortem

What I Learned

1. AI Assisted Analysis is a Force Multiplier Windsurf Cascade AI helped accelerate the documentation process by at least 10X. It excelled at recognizing patterns across hundreds of COBOL files and used those patterns and search capability to build comprehensive documentation. This approach saved tens of hours of analysis and reduced the need to reverse-engineer COBOL code manually. But, it also highlighted a limitation which is very critical: AI can summarize and pattern match well, but can't infer business intent or regulatory nuance. I learned that AI-generated documentation must be treated as a first draft, not final source of truth. Validation with subject matter experts and existing stakeholders is necessary to confirm accuracy, intent, and compliance. 2. Business Requirements to Modern Tooling While modernizing the system into Java and Spring services is the end goal, this work reinforced the importance of understanding business requirements before starting architecture decisions. I intentionally left out service designs or data models and solely focused on extracting and documenting what the system does and why. The document produced will now serve as the foundation the future work will build on.

Metrics & Impact

Documented 25+ business rules Five COBOL jobs translated including: decision logic, error handling, and architecture recommendations

Background

A legacy mainframe subsystem consists of five interdependent COBOL batch jobs responsible for identifying, matching, and merging customer records. These jobs operate as an automated pipeline with tightly coupled execution order and shared data dependencies. The system suffers from a significant documentation gap: business logic and technical specifications are fragmented across 100+ files, with no centralized or authoritative source of truth. The business objective is to re-platform this functionality into a modern Java and Spring Boot microservices architecture while preserving existing behavior, data integrity, and regulatory compliance.

Daily Timeline