Cobol Modernization

End-to-end workflow for migrating COBOL codebases to Java.

Overview

This plugin orchestrates a multi-phase COBOL modernization project:

1. Build Setup — Configure compilation for both COBOL and Java, create test fixtures
2. Mainframe Planning — Document transformations needed to remove mainframe dependencies
3. Mainframe Removal — Convert CICS/VSAM code to standard COBOL
4. Java Migration — Translate standardized COBOL to idiomatic Java

Prerequisites

• GnuCOBOL compiler (cobc)
• Java 11+ with Maven or Gradle
• Python 3.13 with uv
• LLM API key (Anthropic or OpenAI)

Quick Start

export LLM_API_KEY="your-api-key"
export LLM_MODEL="anthropic/claude-3-5-sonnet-20241022"

uv run python -m lc_sdk_examples.cobol_modernization --src-path /path/to/cobol/project

PowerShell equivalent for the environment setup:

$env:LLM_API_KEY = "your-api-key"
$env:LLM_MODEL = "anthropic/claude-3-5-sonnet-20241022"

uv run python -m lc_sdk_examples.cobol_modernization --src-path C:\path\to\cobol\project

Workflow Phases

Phase 1: Build Setup

See ../build-setup/SKILL.md

Creates the foundation for the migration:

• COBOL compilation environment (GnuCOBOL)
• Java project structure (Maven/Gradle + JUnit 5)
• Test fixtures with golden outputs from COBOL execution

Outputs:

• build_notes.md — Build instructions
• test-fixtures/ — Input/output test data
• test_manifest.json — Test case mapping

Phase 2: Mainframe Planning

See ../mainframe-planning/SKILL.md

Creates a transformation guide without modifying code:

• Maps CICS/VSAM constructs to standard COBOL equivalents
• Documents error handling replacements
• Identifies UI operations to stub

Output:

• mainframe_dependency_removal_plan.md

Phase 3: Mainframe Removal

See ../mainframe-removal/SKILL.md

Applies the transformation guide:

• Replaces EXEC CICS commands with file I/O
• Adds FILE STATUS checking
• Stubs BMS/screen operations

Verification:

• Code compiles with GnuCOBOL
• Runs with test fixtures

Phase 4: Java Migration

See ../to-java-migration/SKILL.md

Translates to idiomatic Java:

• Proper Java conventions (not literal translations)
• JUnit tests using golden outputs
• COBOL references in comments

Done when:

• All code compiles
• All JUnit tests pass
• No TODOs or stubs remain

Output Structure

your-project/
├── .lc-sdk/
│   ├── initial_batch_graph.json
│   ├── fixed_batch_graph.json
│   └── mainframe_dependency_removal_plan.md
├── test-fixtures/
│   ├── inputs/
│   └── expected_outputs/
├── test_manifest.json
├── src/main/java/
└── src/test/java/

Troubleshooting

See ../../references/troubleshooting.md for common issues and solutions.