Smart Wallet Application

A server-rendered wallet service built with Spring Boot. Users hold multiple currency wallets, transfer funds to each other, and move between subscription tiers that are charged against a wallet balance.

Try the demo · Documentation

The demo is the application's own templates and stylesheets running against a seeded registry in the browser, so transfers, top-ups and subscription upgrades all work with no backend behind them. It opens on a couple of months of seeded movements, which is what the analytics page reads. State lives in sessionStorage, and reloading the page starts the demo over on the login screen.

Requirements

• JDK 17
• MySQL on localhost:3306 (the dev profile creates the schema on first run)

The Maven wrapper is checked in, so no local Maven install is needed.

Running

./mvnw spring-boot:run

The app starts on http://localhost:8080 and seeds the default user configured in src/main/resources/application.properties.

Without a database

To boot against an in-memory H2 instead — the same thing CI does:

./mvnw clean package
java -jar target/smart-wallet-application-*.jar \
  --spring.datasource.url='jdbc:h2:mem:local;DB_CLOSE_DELAY=-1' \
  --spring.datasource.driverClassName=org.h2.Driver \
  --spring.datasource.username=sa \
  --spring.datasource.password= \
  --spring.jpa.hibernate.ddl-auto=create-drop

Profiles

dev is active by default. Deploy with --spring.profiles.active=prod and supply DB_URL, DB_USERNAME and DB_PASSWORD as environment variables.

Quality gates

./mvnw checkstyle:check   # style
./mvnw clean verify       # build and test

Both run in CI on every push and pull request against master, followed by a smoke test that boots the packaged jar. Checkstyle rules live in config/checkstyle/checkstyle.xml.

Layout

Packages are organised by feature rather than by layer.

Package	Holds
app.user, app.wallet, app.transaction, app.subscription	Model, repository and service per feature
app.analytics	Reads transactions back as a spending summary
app.web	Controllers, DTOs and mappers
app.security	UserDetails implementation
app.notification, app.init	OpenFeign clients for other services
app.event, app.email, app.gift	Application events and their listeners