LLM-Assisted Legacy System Migration to Modern Java
Turn legacy Java into maintainable, standards-based, zero-dependency code. Learn how to extract specs and tests from existing applications, then migrate incrementally to modern JDKs, BCE, and MicroProfile, with LLMs and agents doing the mechanical work, and tests as verification loops.
🎯 Agenda
- Reverse-engineering intent from undocumented legacy code
- Extracting the ubiquitous language from legacy code
- Ubiquitous language as migration compass: naming BCs, boundaries and entities
- Capturing the structure of existing databases with custom MCPs: exposing schemas to LLMs for context-aware migration
- Extracting characterization tests from existing applications: verification loops for the migration
- Spec-driven BCE (say "Space") migrations with SBCE
- LLM-assisted creation of OpenRewrite rules: generating recipes for repeatable, large-scale migrations
- Defining custom skills to capture transformation rules: reusable, shareable migration knowledge for developers and agents
- Automating migrations with purpose-built agents
- Pruning dependencies and custom frameworks for security, productivity and maintainability
- Migrating custom-grown frameworks to Java SE and LLM-friendly standards with stable APIs and normative specifications (e.g. MicroProfile)
- Replacing external dependencies with standards: more security, less maintenance
- Traceability: mapping legacy components to their migrated counterparts for auditable, verifiable migrations
- TBD
🔗 References
- bce.design — Boundary, Control, Entity architecture
- bce.space — Spec-Driven BCE
- airails.dev — AI rails for Java development
📋 Prerequisites & Setup
I will build enterprise Java applications iteratively with LLMs, answer your questions, and implement features on the fly. You will receive a Git repository containing all intermediate steps and a deployable application.
Required Software:
- Java 25
- Git client
- Maven 3
💡 Note: You can follow along or take notes — all source code will be provided!
🚀 80% hands-on coding — The workshop adapts to your questions!
📧 Questions or Direct Registration?
Contact: workshops[-AT-]adam-bien.com
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📄 Note: Invoice available through Eventbrite registration