Pragmatica

Java Backend Coding Technology

Free web edition of the complete JBCT book. For a portable PDF with cover art, see Get the PDF.

Part I: Foundations

Chapter	Description
Chapter 1: Introduction - Code Unification	Why structural standardization matters in the AI era and what JBCT sets out to solve.
Chapter 2: From Process to Patterns	Process-first design methodology — how to go from requirements to code structure mechanically.
Chapter 3: The Four Return Types	Why exactly four return types are sufficient and when to use each one.
Chapter 4: Pragmatica Core Essentials	The minimal Pragmatica Core API surface you need to get started.

Part II: Core Principles

Chapter	Description
Chapter 5: Parse, Don’t Validate	Make invalid states unrepresentable using factory-method construction.
Chapter 6: Error Handling & Composition	Errors as typed values, clean monadic composition, and when exceptions are still acceptable.
Chapter 7: Null Policy & Error Recovery	When null is acceptable at adapter boundaries and how to recover gracefully.

Part III: Patterns

Chapter	Description
Chapter 8: Basic Patterns & Structure	Leaf, Condition, Iteration — the three building blocks that handle 80% of daily coding.
Chapter 9: Advanced Patterns	Sequencer, Fork-Join, and Aspects for composing sophisticated workflows.
Chapter 9b: Knowledge-Gathering Pipelines	Specialised pattern for assembling context from multiple independent sources.
Chapter 10: Thread Safety	Thread-safety guarantees per pattern and how Promise handles concurrency.

Part IV: Testing

Chapter	Description
Chapter 11: Testing Philosophy	Integration-first testing — why testing composition beats testing components.
Chapter 12: Testing in Practice	Organisation, parameterised tests, and the evolutionary stub-to-production workflow.

Part V: Production Systems

Chapter	Description
Chapter 13: Complete Example - RegisterUser	A full use case walkthrough from requirements through tests.
Chapter 14: Complete Example - PlaceOrder	Multi-step order placement with Fork-Join and error recovery.
Chapter 15a: Focused Example - PublishArticle	External-service integration using the Sequencer pattern.
Chapter 15b: Focused Example - TransferFunds	Transactional safety and rollback with typed errors.
Chapter 16: Project Structure & Framework Integration	Vertical slicing, package layout, and connecting to Spring Boot and JOOQ.

Part VI: Adoption

Chapter	Description
Chapter 17: Systematic Application Guide	Eight checkpoints for coding and review that enforce 100% JBCT compliance.
Chapter 18: Migration Strategies	Incremental adoption — how to migrate existing codebases without a big-bang rewrite.
Chapter 19: Comparison with Other Approaches	How JBCT compares to traditional OO, Spring idioms, and other functional styles.
Chapter 20: Troubleshooting & FAQ	Common mistakes, compiler errors, and answers to frequently asked questions.

Appendices

Appendix	Description
Appendix A: Pragmatica Core API Reference	Complete API reference for Result, Option, Promise, and utility types.
Appendix B: Exercises and Solutions	Practice exercises for each major topic with worked solutions.
Appendix C: Glossary	Definitions for every term used throughout the book.