If you find a PDF claiming to be the exact copy of "Designing Hexagonal Architecture with Java" (ISBN 978-1617294545) for free, it is likely pirated. Support the authors who push Java forward. Implementing What You Learn: A 2021 Project Setup Once you download your resource, here is the recommended Maven/Gradle structure you will find inside:
com.mybankapp/ ├── domain/ (No dependencies) │ ├── model/ (Account, Customer) │ └── exception/ (DomainRuleViolation) ├── application/ (Use cases & Ports) │ ├── port/in/ (Input ports: CreateAccountUseCase) │ ├── port/out/ (Output ports: LoadAccountPort) │ └── service/ (Implements the Use Cases) ├── infrastructure/ (Adapters) │ ├── web/ (RestControllers) │ ├── persistence/ (JPA Repositories) │ └── messaging/ (Kafka/RabbitMQ listeners) └── shared/ (Helpers, Annotations) If you are building Java applications in 2025 , the 2021 PDF is still remarkably relevant. Hexagonal Architecture is a timeless pattern, unlike a JavaScript framework. Java 17 (LTS) works identically to Java 11 for these patterns. If you find a PDF claiming to be
// Constructor injection (Spring 5+ / Boot 2.4+) public WithdrawController(WithdrawMoneyPort withdrawUseCase) { this.withdrawUseCase = withdrawUseCase; } Hexagonal Architecture is a timeless pattern, unlike a
Stop designing brittle monoliths. Start designing hexagons. Note: This article is for educational purposes. Always respect copyright laws and intellectual property when downloading digital assets. Start designing hexagons
public void withdraw(Money amount) { if (balance.lessThan(amount)) { throw new InsufficientFundsException(); } this.balance = this.balance.minus(amount); } } package com.mybank.application.ports; public interface WithdrawMoneyPort { void withdraw(Long accountId, Money amount); } 3. The Adapters (Spring Boot example for 2021) @RestController // Adapter for Web public class WithdrawController { private final WithdrawMoneyPort withdrawUseCase; // The Port