Why We Choose Java and Spring Boot

Introduction

When building STSTSI Commerce, we had to make critical technology stack decisions that would impact our platform's performance, maintainability, and scalability for years to come. After careful evaluation of various options, we chose Java with Spring Boot as the foundation of our platform. Here's why.

Today, STSTSI Commerce runs as a modular architecture with nine modules—four runnable applications and five shared libraries. The applications include Commerce Manager for administration, Commerce Reference Store API for customer interactions, Commerce Integration Service for external integrations, and Commerce Batch Service for scheduled tasks. All built on Spring Boot, sharing common libraries, and deployed independently for maximum flexibility.

Enterprise-Grade Maturity

Java has been battle-tested in enterprise environments for over two decades. This isn't just about legacy—it's about proven reliability. The JVM (Java Virtual Machine) has been optimized for performance and stability across millions of production deployments, giving us confidence that our platform can handle mission-critical commerce operations.

Spring Boot, as an evolution of the Spring Framework, brings this maturity into the modern era with convention-over-configuration principles that accelerate development without sacrificing enterprise capabilities. It's the perfect balance of productivity and power.

Robust Ecosystem and Libraries

The Java ecosystem offers unparalleled depth of high-quality libraries and frameworks. For a commerce platform, this means:

• Spring Data JPA for seamless database interactions
• Spring Security for comprehensive authentication and authorization
• Spring HATEOAS for building hypermedia-driven REST APIs
• Hibernate for powerful ORM capabilities
• Jackson for JSON processing
• Liquibase for database migrations
• OpenSearch 3.1.0 for full-text search and faceted filtering
• Kogito/Drools 10.1.0 for business rules and promotion engine

These aren't just libraries—they're mature, well-documented solutions maintained by vibrant communities and backed by major organizations. We don't have to reinvent the wheel for common e-commerce requirements.

For example, Spring Data JPA allows us to define data access patterns declaratively—the framework generates all the implementation code automatically. This means less code to write, test, and maintain, while getting battle-tested database operations out of the box. We have 20+ data repositories across the platform, saving thousands of lines of boilerplate code.

Type Safety and Compile-Time Checking

Java's static typing catches many bugs before they reach production. For a commerce platform handling real transactions and sensitive customer data, this compile-time safety net is invaluable. We catch type mismatches, null pointer issues, and interface contract violations during development, not in production.

Combined with modern Java features like Optional, record types, and pattern matching, we write code that's both safe and expressive. The language has evolved significantly since Java 8, and we leverage these improvements throughout our codebase.

Spring Boot's Developer Experience

Auto-Configuration

Spring Boot's intelligent auto-configuration means we can get started quickly without boilerplate. Adding a dependency automatically configures sensible defaults, which we can customize as needed. This accelerates development while maintaining flexibility.

Embedded Server

No need for external application servers. Spring Boot packages our application with an embedded Tomcat or Netty server, making deployment as simple as running a JAR file. This aligns perfectly with modern containerized deployment strategies.

Spring Boot Actuator

Production-ready features like health checks, metrics, and monitoring come out of the box. We can integrate with monitoring systems, set up custom health indicators, and get detailed insights into our application's behavior in production. Applications start in seconds and are production-ready out of the box.

Performance and Scalability

Modern JVM performance is exceptional. JIT (Just-In-Time) compilation optimizes hot code paths at runtime, often approaching or exceeding the performance of statically compiled languages for long-running applications—perfect for server-side e-commerce systems.

Spring Boot's support for reactive programming through Spring WebFlux (using Project Reactor) gives us options for handling high-concurrency scenarios efficiently. We can choose between traditional servlet-based or reactive architectures based on specific use cases.

Strong Community and Corporate Backing

Spring is maintained by VMware (via Pivotal) with significant contributions from the global Java community. This means:

• Regular updates and security patches
• Extensive documentation and guides
• Large talent pool of experienced developers
• Comprehensive training resources
• Long-term support and stability

For enterprises, this backing provides confidence that the technology won't be abandoned and that help is readily available when needed.

Database and Transaction Management

E-commerce requires robust transaction management. Spring's declarative transaction support with @Transactional makes it straightforward to ensure data consistency across complex operations. Combined with Spring Data JPA, we get powerful database abstractions without sacrificing control when we need it.

Order creation is a perfect example—it's a complex multi-step process involving cart validation, price verification, tax calculation, and inventory reservation. All of these must succeed together or roll back entirely. Spring's declarative transaction management handles this automatically. If any step fails, the entire operation rolls back, and database consistency is guaranteed without writing manual transaction management code.

Security First

Spring Security provides enterprise-grade authentication and authorization out of the box. For a commerce platform handling sensitive customer data and financial transactions, this is non-negotiable. We get protection against common vulnerabilities like CSRF, session fixation, and clickjacking automatically.

The framework's flexibility allows us to implement sophisticated security requirements—OAuth2, JWT, custom authentication providers—without starting from scratch.

Testing Support

Spring Boot's testing support is comprehensive. From unit tests to integration tests, the framework provides utilities that make testing straightforward:

• @SpringBootTest for full application context testing
• @WebMvcTest for controller layer testing
• @DataJpaTest for repository testing
• MockMvc for API testing without starting a server
• Testcontainers integration for real database testing

This comprehensive testing support helps us maintain high code quality and confidence in our releases.

Extensibility Through Java SPI

One of Java's most powerful but underutilized features is the Service Provider Interface (SPI) pattern. We use it extensively in STSTSI Commerce to create a plugin architecture for payment providers, allowing seamless integration with Stripe, Square, Moneris, and custom processors without modifying core code.

Our payment provider architecture uses Java's Service Provider Interface (SPI) pattern. This means merchants can add custom payment integrations simply by adding a plugin—no core code changes required. The platform automatically discovers and loads payment providers at runtime.

Out of the box, we support Stripe for North America, Square for retail, and Moneris for Canadian markets. Each provider implements the same standardized interface for processing payments, capturing authorizations, handling refunds, and verifying webhooks. Adding a new payment provider is as simple as implementing this interface and dropping in a JAR file.

Modular Monolith Architecture

STSTSI Commerce implements a modular monolith pattern that provides clean separation of concerns while maintaining deployment simplicity. Our architecture consists of nine modules—four runnable applications and five shared libraries:

Runnable Applications

• commerce-manager: Admin application for product, order, and customer management
• commerce-storefront-api: Customer-facing HATEOAS REST API
• commerce-integration: External integrations—email notifications, webhooks
• commerce-batch: Scheduled batch processing—reports, data exports, cleanup

Shared Libraries

• commerce-core: Shared entities, repositories, and business logic
• commerce-search: OpenSearch 3.1.0 integration with faceted search, autocomplete, and spell-check
• commerce-promotions: Kogito/Drools 10.1.0 rules engine for promotions and discounts
• commerce-extensions: SPI definitions and plugin architecture for payment providers
• commerce-messaging: Event-driven communication via RabbitMQ

Each module can be deployed independently or together, giving us deployment flexibility without the operational complexity of distributed systems. Spring Boot's flexible packaging and embedded servers make deployment straightforward—each application is a simple JAR file that can run standalone.

Why Modular Monolith Over Microservices

We deliberately chose a modular monolith architecture over microservices. While microservices have their place, they introduce significant operational overhead: distributed tracing, service discovery, network latency, eventual consistency challenges, and complex deployment pipelines.

For e-commerce, where transactional consistency matters and most operations span multiple domains (products, inventory, orders, payments), a modular monolith provides the right balance. We get clean module boundaries, independent services when needed, and ACID transactions across the entire business operation—all without the complexity of distributed systems.

The modular structure gives us other benefits too: focused smoke testing verifies each service can start independently, shared code lives in commerce-core, and developers can work on different modules without conflicts. Spring Boot makes this pattern natural and productive.

Real-World Results

The proof is in the implementation. Today, STSTSI Commerce runs on:

• Java 21 with modern language features
• Spring Boot 3.5.7 with the latest framework improvements
• OpenSearch 3.1.0 (Lucene 10.2) for high-performance search
• Kogito/Drools 10.1.0 powering the promotions and business rules engine
• 20+ Spring Data repositories handling all data access
• 4 payment providers via our SPI architecture (Stripe, Square, Moneris, Mock)
• 9 modules—4 runnable applications and 5 shared libraries
• Automated smoke tests verifying all services start correctly in ~60 seconds
• Liquibase migrations managing 144 database changesets automatically
• Spring Security protecting all endpoints with JWT authentication
• Spring Boot Actuator providing health checks and metrics for production monitoring
• Docker support with multi-stage builds for optimized container images

Our applications start in under 6 seconds, include embedded Tomcat servers, and can be deployed as simple JAR files. The entire platform builds and tests in minutes, and our automated smoke test suite ensures reliability across all services.

Conclusion

Choosing Java and Spring Boot for STSTSI Commerce wasn't about following trends—it was about selecting proven technologies that align with enterprise requirements for reliability, security, and maintainability. The ecosystem's maturity, combined with Spring Boot's modern developer experience, gives us the best of both worlds.

The code examples in this article aren't hypothetical—they're from our actual production codebase. The modular architecture, extension system, transaction management, and repository patterns all work together to create a maintainable, scalable e-commerce platform that we're confident will serve our customers for years to come.

For organizations building commerce platforms that need to scale, remain secure, and be maintained over many years, Java and Spring Boot remain an excellent choice. The technology stack you choose today will impact your development velocity and operational stability for years to come—we're confident we made the right choice.