[VDBUH2026] Julien Topçu - Hexagonal Architecture in Practice

A conference talk transcript demonstrating Hexagonal Architecture (Ports and Adapters) in practice using Java and Spring Boot. The speaker contrasts classic layered architecture's coupling problems with the hexagonal approach, which isolates business logic in a domain module free of framework dependencies. Through live coding, the talk shows how to define API and SPI interfaces, implement adapters (REST controller and external web service client), use stubs for parallel development, apply anti-corruption layers to prevent external data models from contaminating the domain, and keep REST resource representations separate from domain objects to avoid breaking API consumers during refactoring.