• JDK 21 - Core language
• Spring Boot 3.3 - Java Framework
• Maven - Build tool
• Junit5 - Unit Testing
• Mockito - Mocking objects while Unit testing
• AssertJ - Simple assertion style while Unit testing
• Lombok - Auto generates boilerplate code for POJOs
• Hibernate/Spring Data JPA - Persistence Implementation Framework
• MySql - Database
• TestContainers - A framework that allows us to launch a MySQL database as a Docker container from tests.
• Docker - To run MySQL and Sonar as containers. Just install Docker Desktop and done
• Jacoco - To analyze code coverage
• SonarQube - To analyze and report bugs and issues
• Spotless - To analyze and format the code
• Static Code Analysis - By SpotBugs, PMD, Google Checkstyle (If using Sonar then not req as most of the rules are now part of Sonar)
• Slf4j/CustomLog - Slf4j Logging support using Lombok CustomLog
• Swagger - OpenAPI which is the version 3 implementation for Spring Boot 3.x

• React 18 - JSX Framework
• React Router - Navigation
• Vite JS - React development Server
• SWC - Speedy Web Compiler
• Bootstrap 5 - CSS
• Axios - Rest API Calls
• FontAwesome - SVG Icons

• HTTP Client - Required to run sample http commands from document/sample-requests.http (Step 1,2)
• JUnit
• Lombok
• Spring DATA
• Tomcat
• Jakarta EE - Application server
• Vite

Alistair Cockburn introduced the hexagonal software architecture as follows

• All non-technical business logic must reside in Application core and must be invoked by User, External application or automated Tests without any difference.
• All communication to the Application core from external entities say User, Database or Test suite must happen through Ports (Interfaces).
• An Adapter is like a middleman who will control the communication between External entities and Application core via Ports.

The application mimics a simplified online store with following functionalities:

• Add, Remove and Edit Products
• Product search
• Adding a product to the shopping cart
• Retrieving the shopping cart with the products, their respective quantity, and the total price
• Incrementing, Decrementing or removing an Item from Cart
• Emptying the shopping cart

• The amount of a product added to the cart must be at least one.
• After adding a product, the total quantity of this product in the cart must not exceed the amount of the product available in the warehouse or 10 which ever is smaller.
• After emptying the Cart there should be no products available in the Cart.
• We can not remove a Product if it is present in any Cart.

The source code has four modules:

• model - It contains the domain models
• application - It contains the domain services and the ports
• adapter - It contains the adapters like REST, In-memory and JPA
• boostrap - It contains the configuration and bootstrapping logic like instantiating adapters/domain services and running Undertow web server

The following diagram shows the final hexagonal architecture of the application along with the source code modules.

Hexagonal Architecture modules (www.happycoders.eu)

• @RequiredArgsConstructor - Generates constructor that take one argument per final / non-nullfield
• @AllArgsConstructor - Generates constructor that take one argument for every field.
• @Data - A shortcut for @ToString, @EqualsAndHashCode, @Getter on all fields, and @Setter on all non-final fields, and @RequiredArgsConstructor!
• @Accessors
• • fluent – A boolean. If true, the getter for pepper is just pepper(), and the setter is pepper(T newValue). Furthermore, unless specified, chain defaults to true. Default: false.
• • chain – A boolean. If true, generated setters return this instead of void. Default: false, unless fluent=true, then Default: true.
• @Getter/@Setter - Generates getter/setter methods for the fields
• @ToString - Generates a toString method for the class
• @EqualsAndHashCode - Generates hashCode and equals implementations from the fields of your object
• @CustomLog - Generates Custom Logger object for the class based on Logging library as defined in lombok.config file

lombok.log.custom.declaration = org.slf4j.Logger org.slf4j.LoggerFactory.getLogger(NAME)(TOPIC)

• Build and run the Bootstrap.war in Tomcat
• Spring Boot Profile - Use the Spring boot profile mysql while running the app. Default is inmemory

-Dspring.profiles.active=mysql

• Based on the System property value of 'persistence' key ('inmemory'/'mysql') we can run the application with
• InMemory DB - Data will persist till the application is running
• MySql DB - We can either run a local MySql server (DB-shop, Root Pwd-test) or run a Docker container

docker run --name hexagon-mysql -d -p3306:3306 -e MYSQL_DATABASE=shop -e MYSQL_ROOT_PASSWORD=test mysql:8.1

• You can invoke HTTP commands from 'documents/sample-requests.http' directly from Intellij

• Go to shop-frontend folder and run node server

cd shop-frontend
npm run dev

• Spotless - run mvn spotless:apply to auto reformat the code if there is any issue during build
• Static code analysis - For Static code analysis with Spotbugs, PMD and Google Check style run

mvn clean verify -Dspring.profiles.active=code-inspection -DskipTests=true

• As per May 2024, Sonar supports up to JDK17 with some issues with ElasticSearch.
• So if you have any latest version of JDK installed then please install JDK 17 separately.
• Create an Environment variable to point to the Java executable file of JDK17 i.e.

SONAR_JAVA_PATH = C:\Program Files\Java\jdk-17.0.1\bin\java.exe (Windows)

• And run the StartSonar.bat

C:\sonarqube\bin\windows-x86-64\StartSonar.bat

• Please refer the https://docs.sonarsource.com/sonarqube/latest/try-out-sonarqube/ page for latest steps

• If Docker is already installed on your system (as part of MySql TestContainers step)
• Then just execute the following line and you are all set

docker run -d --name sonarqube -e SONAR_ES_BOOTSTRAP_CHECKS_DISABLE=true -p 9000:9000 sonarqube:latest

mvn -Dsonar.projectKey=<<PROJECT_KEY>> -Dsonar.projectName='<<PROJECT_NAME>>' -Dsonar.host.url=http://localhost:9000 
-Dsonar.token=<<TOKEN_VALUE>> clean verify sonar:sonar

• Swagger UI - http://localhost:8080/shop/swagger-ui/index.html
• Client Docs - http://localhost:8080/shop/v3/api-docs