Enterprise Spring Boot Architecture Blueprint
Foundational 5-layer enterprise backend architecture on Java 21 LTS and Spring Boot 3.3
Establish an unshakeable architectural foundation. Build a 5-layer production Spring Boot 3.3 system incorporating Java 21 Virtual Threads (Loom), Flyway migrations, BigDecimal financial rounding, JPA @Version optimistic concurrency, AES-GCM field encryption, stateless JWT filters, Redis caching with write-eviction, Resilience4j circuit breakers, and Testcontainers integration tests.
Course Prerequisites
- Core Java syntax (collections, streams, OOP, exceptions).
Part of Academy Track:
What You Will Master
Curriculum Modules (5 Modules)
Explore the structured module breakdown, lesson outcomes, and practical lab exercises.
Module 1: Foundations & Architecture
6 Lessons • ~8.6 Study Hours (0.86 CEUs)Welcome to Module 1: Foundations & Architecture. In this section of the curriculum, learners dive deep into foundational and advanced principles designed for production application. This module covers: Understand the motivation behind this blueprint — why a production backend needs more than a beginner tutorial and how the five sections build on each other.; Configure Java 21 LTS, Gradle Kotlin DSL, and Spring Boot 3.3 project structure from a clean slate with virtual threads and Actuator enabled.; Build the first REST endpoint, expose /actuator/health, and understand why Spring's defaults hide critical endpoints by default..
Course Introduction — Why This Blueprint Exists
Understand the motivation behind this blueprint — why a production backend needs more than a beginner tutorial and how the five sections build on each other.
Project Setup — Java 21 LTS, Gradle & Spring Boot 3.3
Configure Java 21 LTS, Gradle Kotlin DSL, and Spring Boot 3.3 project structure from a clean slate with virtual threads and Actuator enabled.
The First Endpoint & Health Check
Build the first REST endpoint, expose /actuator/health, and understand why Spring's defaults hide critical endpoints by default.
Self-Documenting APIs with OpenAPI & Swagger UI
Integrate Springdoc OpenAPI 3 to auto-generate interactive API documentation directly from controller code — never hand-maintain a spec again.
Layered Architecture — Controller → Service → Repository
Enforce strict three-layer architecture (Controller → Service → Repository), use Java Records for immutable DTOs, and prevent entity leakage into HTTP responses.
Centralized Exception Handling with @RestControllerAdvice
Implement a single @RestControllerAdvice that handles every exception centrally, eliminating try/catch in controllers and ensuring consistent error payloads.
Module 2: Data, Persistence & Safety
8 Lessons • ~11.1 Study Hours (1.11 CEUs)Welcome to Module 2: Data, Persistence & Safety. In this section of the curriculum, learners dive deep into foundational and advanced principles designed for production application. This module covers: Run PostgreSQL 16 in Docker for local dev parity with production, configure datasource properties, and connect Spring Boot to a real relational database.; Replace dangerous spring.jpa.hibernate.ddl-auto with Flyway versioned SQL migrations, ensuring safe, auditable, and reversible schema evolution.; Model JPA entities with correct field types, use BigDecimal (never double/float) for all monetary values, and understand why floating-point math silently corrupts financial systems..
PostgreSQL Setup in Docker — Local Production Parity
Run PostgreSQL 16 in Docker for local dev parity with production, configure datasource properties, and connect Spring Boot to a real relational database.
Schema Control with Flyway (Not `ddl-auto`)
Replace dangerous spring.jpa.hibernate.ddl-auto with Flyway versioned SQL migrations, ensuring safe, auditable, and reversible schema evolution.
Entities & `BigDecimal` — Why Floating-Point Math Is Not Optional
Model JPA entities with correct field types, use BigDecimal (never double/float) for all monetary values, and understand why floating-point math silently corrupts financial systems.
Pagination — Preventing Runaway Queries
Implement Spring Data JPA Pageable queries to prevent runaway memory consumption when data sets grow beyond what fits in a single API response.
Memory Discipline — Streaming Large Datasets
Use ResultSet streaming and Spring Data JPA streams to process large dataset exports and reports without loading millions of rows into the heap.
Optimistic Locking — The Concurrency Bug Most Tutorials Miss
Diagnose and fix the lost-update concurrency bug using JPA @Version optimistic locking combined with Spring Retry @Retryable for transparent conflict resolution.
HikariCP Connection Pool Tuning
Calculate and configure HikariCP minimum-idle, maximum-pool-size, and connection-timeout for production workloads based on thread count and DB capacity.
Protecting Sensitive Fields at Rest with Field-Level Encryption
Implement a reusable JPA AttributeConverter using AES-GCM symmetric encryption to protect sensitive columns (PII, tokens) transparently at the persistence layer.
Module 3: Security & Identity
6 Lessons • ~8.9 Study Hours (0.89 CEUs)Welcome to Module 3: Security & Identity. In this section of the curriculum, learners dive deep into foundational and advanced principles designed for production application. This module covers: Hash passwords correctly using BCrypt with Spring Security's PasswordEncoder — never store plaintext or use reversible hashing algorithms.; Build a complete stateless JWT authentication system: token generation, signature verification, and a JwtAuthFilter that integrates with Spring Security's filter chain.; Enforce endpoint-level permissions using @PreAuthorize and @Secured annotations with Spring Security's method-level RBAC and custom UserDetailsService..
Password Hashing with BCrypt — Never Store Them Plain
Hash passwords correctly using BCrypt with Spring Security's PasswordEncoder — never store plaintext or use reversible hashing algorithms.
Stateless JWT Authentication
Build a complete stateless JWT authentication system: token generation, signature verification, and a JwtAuthFilter that integrates with Spring Security's filter chain.
Role-Based Access Control with @PreAuthorize
Enforce endpoint-level permissions using @PreAuthorize and @Secured annotations with Spring Security's method-level RBAC and custom UserDetailsService.
When to Delegate Auth to Keycloak
Understand when to stop building authentication in-house and delegate to Keycloak for SSO, MFA, social login, and multi-service identity federation.
Rate Limiting — Protecting Endpoints from Abuse
Implement IP-based rate limiting using an in-memory token bucket filter, and understand when to graduate to distributed Redis-backed rate limiting for multi-node deployments.
Idempotency Keys for Money-Moving Endpoints
Implement idempotency keys using a request fingerprint stored in a database table so that network retries on money-moving endpoints never cause duplicate transactions.
Module 4: Performance, Resilience & Integration
6 Lessons • ~8.5 Study Hours (0.85 CEUs)Welcome to Module 4: Performance, Resilience & Integration. In this section of the curriculum, learners dive deep into foundational and advanced principles designed for production application. This module covers: Configure Redis 7 as a write-evict caching layer with @Cacheable and @CacheEvict to serve high-frequency reads without hitting the database on every request.; Wrap outbound RestClient HTTP calls in Resilience4j circuit breakers, timeouts, and retry policies to prevent a slow downstream service from cascading into your API.; Implement async webhooks using @Async and Spring's task executor so that outbound event notifications never block the calling HTTP thread or degrade response latency..
Caching with Redis — Write-Evict Strategy
Configure Redis 7 as a write-evict caching layer with @Cacheable and @CacheEvict to serve high-frequency reads without hitting the database on every request.
Outbound HTTP with Resilience4j — Circuit Breakers & Retries
Wrap outbound RestClient HTTP calls in Resilience4j circuit breakers, timeouts, and retry policies to prevent a slow downstream service from cascading into your API.
Async Webhooks — Sending Data Without Blocking the Caller
Implement async webhooks using @Async and Spring's task executor so that outbound event notifications never block the calling HTTP thread or degrade response latency.
Structured Concurrency with Java 21 StructuredTaskScope
Use Java 21 StructuredTaskScope to run multiple concurrent subtasks with automatic cancellation, clear ownership, and scoped lifecycle management.
Beyond REST — GraphQL & gRPC for Alternative API Shapes
Implement a GraphQL endpoint using Spring for GraphQL and a gRPC service using Protocol Buffers for inter-service communication beyond REST.
When to Actually Split into Microservices
Apply concrete decision criteria for microservices decomposition — team ownership boundaries, data isolation, deployment independence, and failure domain containment.
Module 5: Testing, Deployment & Operations
9 Lessons • ~12.6 Study Hours (1.26 CEUs)Welcome to Module 5: Testing, Deployment & Operations. In this section of the curriculum, learners dive deep into foundational and advanced principles designed for production application. This module covers: Structure unit tests with Mockito and integration tests with @SpringBootTest + Testcontainers, keeping them strictly separated in Gradle source sets.; Build a minimal JRE Docker image using a multi-stage Dockerfile, configure docker-compose.yml to orchestrate the API alongside PostgreSQL and Redis with healthcheck gating.; Configure a GitHub Actions CI pipeline that fails builds on test failures, code coverage drops, or SpotBugs static analysis violations before any artifact is produced..
Testing at Two Levels — Unit Tests & Integration Tests
Structure unit tests with Mockito and integration tests with @SpringBootTest + Testcontainers, keeping them strictly separated in Gradle source sets.
Containerizing the Application — Multi-Stage Docker & Compose
Build a minimal JRE Docker image using a multi-stage Dockerfile, configure docker-compose.yml to orchestrate the API alongside PostgreSQL and Redis with healthcheck gating.
CI/CD That Gates on Quality
Configure a GitHub Actions CI pipeline that fails builds on test failures, code coverage drops, or SpotBugs static analysis violations before any artifact is produced.
Zero-Downtime Deployments — Blue-Green & Canary
Implement blue-green and canary deployment patterns using Kubernetes labels to achieve zero-downtime releases and instant rollback capability.
Feature Flags — Decoupling Deployed from Released
Integrate Unleash feature flags to decouple deployment from feature release, enabling per-user, per-tenant, or percentage-based feature toggles without redeployment.
Auditability — Who Did What, When
Implement a JPA-backed audit trail recording every write operation (actor, timestamp, entity, change delta) for regulatory compliance and forensic investigation.
Observability — Logs, Metrics & Distributed Traces
Configure all three observability pillars: structured JSON logging with MDC correlation IDs, Micrometer metrics exposed to Prometheus, and OpenTelemetry distributed tracing.
Proving It Holds Up Under Load — k6 & Gatling
Write a k6 load test script with virtual user ramps and latency SLO thresholds, and a Gatling Scala simulation to prove the API holds up before production traffic hits.
Backups & Disaster Recovery — The Plan for When Things Go Wrong
Automate PostgreSQL WAL-based backups to S3 with integrity validation, configure point-in-time recovery, and run a full restore drill to verify the backup is actually usable.
Enterprise Java & Spring Boot Progression
Continue advancing through the sequential curriculum stages of this academy track: