A banking API implemented with MicroProfile, powered with Quarkus, demonstrating Java 21+ features. The application provides account management and transaction processing capabilities with a focus on simplicity, observability, and testability.

The application follows the Boundary-Control-Entity (BCE/ECB) pattern pattern to maintain clear separation of concerns.

Use the provided script for quick database setup:

./runDB.sh

Or manually:

docker pull postgres
docker run --rm --name ebank-postgres -e POSTGRES_USER=ebank -e POSTGRES_DB=ebankdb -e POSTGRES_PASSWORD=ebanksecret -p 5432:5432 -d postgres

cd ebank
mvn quarkus:dev

cd ebank-st
mvn failsafe:integration-test

• Quarkus: Supersonic subatomic Java framework optimized for cloud deployments
• PostgreSQL: Popular relational database for transaction consistency
• Jakarta Persistence (JPA): Standard ORM for domain object mapping
• Jakarta REST: RESTful web services following industry standards
• MicroProfile Health: Production-ready health check endpoints
• MicroProfile Metrics: Application performance monitoring

This project demonstrates several Java and architectural conventions:

• BCE/ECB Pattern: Boundary-Control-Entity pattern for clear separation of concerns
• Package by Feature: Components organized by business domain (accounting, bonus, reporting, logging)
• Domain-Driven Package Naming: Packages named after their responsibilities, not technical layers
• Custom Stereotype Annotations: @Boundary annotation combining @ApplicationScoped and @Transactional

• Package-info Files: Documentation at package level describing domain responsibilities
• Package-Private Visibility: Preferred over private fields
• Meaningful Names: Classes named after responsibilities, avoiding generic suffixes (*Impl, *Service, *Manager)

• Records: Immutable data carriers (AccountCreationResult, BonusResult)
• Sealed Interfaces: Transaction interface with controlled implementations
• Pattern Matching: Enhanced switch expressions for type-safe handling
• var Keyword: Local variable type inference for cleaner code

• JAX-RS Resources: REST endpoints with HTTP verbs
• Response Builders: Centralized response creation with status codes
• OpenAPI Annotations: Schema definitions for API documentation
• Metrics Integration: @Timed annotations for performance monitoring

• JPA Entities: Simple entities with public fields
• EntityManager Usage: Direct use via @PersistenceContext
• JDBC for Reporting: Direct JDBC usage in reporting component for optimized read operations
• Optional Pattern: Consistent use of Optional for nullable returns
• Factory Methods: Static factory methods in entities

• CDI Integration: Jakarta CDI with @Inject for dependencies
• Custom Logger: Centralized EBLog component for logging

• Stream API: Preference for streams over traditional loops
• Method References: Used instead of verbose lambda expressions
• Immutable Results: Result types as records

• AssertJ Library: Fluent assertions instead of JUnit assertions
• Essential Tests Only: Avoiding repetitive tests, focusing on core functionality
• Integration Tests: Suffix with "IT" for Failsafe plugin execution

• KISS: Keep It Simple - simplest possible solutions
• YAGNI: You Aren't Gonna Need It - no over-engineering
• High Cohesion: Classes with single, well-defined responsibilities
• Low Coupling: Minimal dependencies between components