shashankch · shashankch · Jul 30, 2026 · Jul 30, 2026
diff --git a/.gitignore b/.gitignore
@@ -37,3 +37,4 @@ build/
 
 ### Internal docs (not committed) ###
 internal/
+internal/*
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -18,6 +18,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Repository contribution guidelines and branch protection rules (`CONTRIBUTING.md`).
 - GitHub status badges in `README.md`.
 
+### Fixed
+- Dockerfile JDK version mismatch: `eclipse-temurin:21-jre` → `eclipse-temurin:25-jre` to align with project's `java.version`.
+- Broken GraalVM native profile in `pom.xml`: removed invalid dependency declaration with undefined property reference.
+- Removed `System.out.println` debug statement from `UserController`.
+- README updated to accurately reflect current project status.
+
 ---
 
 ## [0.1.0] - 2026-07-27

diff --git a/Dockerfile b/Dockerfile
@@ -1,4 +1,4 @@
-FROM eclipse-temurin:21-jre AS runtime
+FROM eclipse-temurin:25-jre AS runtime
 
 WORKDIR /app
 

diff --git a/README.md b/README.md
@@ -4,107 +4,95 @@
   <a href="https://github.com/shashankch/payflow-api/actions/workflows/ci.yml"><img src="https://github.com/shashankch/payflow-api/actions/workflows/ci.yml/badge.svg" alt="Build"></a>
   <a href="https://dev.java/"><img src="https://img.shields.io/badge/Java-25-ED8B00?logo=openjdk&logoColor=white" alt="Java 25"></a>
   <a href="https://spring.io/projects/spring-boot"><img src="https://img.shields.io/badge/Spring%20Boot-4.0.6-6DB33F?logo=springboot&logoColor=white" alt="Spring Boot"></a>
-  <a href="https://www.postgresql.org/"><img src="https://img.shields.io/badge/PostgreSQL-17-4169E1?logo=postgresql&logoColor=white" alt="PostgreSQL"></a>
   <a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-yellow.svg" alt="License: MIT"></a>
   <a href="CONTRIBUTING.md"><img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg" alt="PRs Welcome"></a>
 </p>
 
-Payflow is a highly resilient, transactional payments backend built using **Java 25** and **Spring Boot 4.x**. The project is designed with a pluggable, cloud-flexible architecture optimized for local developer iteration, Kubernetes deployment, and resource-constrained environments (like AWS Free Tier and Oracle Cloud Always Free).
+Payflow is a transactional payments backend built using **Java 25** and **Spring Boot 4.x**, designed to evolve from a baseline REST API into an enterprise-grade payment system with ACID guarantees, event-driven architecture, and observability.
 
 ---
 
-## Current Status & Evolution Roadmap
+## Current Status
 
-The project is currently evolving through a phased implementation roadmap from a Phase 0 baseline into an enterprise-grade payment system.
+The project is evolving through a phased implementation roadmap. See the full plan in **[Phased Roadmap](docs/ROADMAP.md)**.
 
-- **Phase 0 (Completed)**: Baseline REST API for User & Transaction CRUD with H2 in-memory storage.
-- **Phase 1 (In Progress)**: Project hygiene, static analysis (Spotless, Checkstyle), and GitHub Actions CI.
-- **Target Phases**: PostgreSQL & Flyway migrations, pessimistic row locking with deadlock avoidance, durable idempotency engine, transactional outbox pattern, JWT security, Resilience4j fault tolerance, Redis caching & Redisson distributed locking, Kafka event streaming, and Gen-AI transaction insights.
-
-See the complete step-by-step evolution in **[Phased Roadmap](docs/ROADMAP.md)**.
+| Phase | Description | Status |
+|-------|-------------|--------|
+| **Phase 0** | Baseline REST API — User & Transaction CRUD with H2 in-memory storage | ✅ Complete |
+| **Phase 1** | Project hygiene — Spotless, Checkstyle, GitHub Actions CI | ✅ Complete |
+| **Phase 2** | Domain model hardening, DTO layer, validation, error handling | ⬜ Not Started |
+| **Phase 3+** | Concurrency control, Flyway, security, observability, and more | ⬜ Not Started |
 
 ---
 
-## Technical Architecture Highlights
+## Implemented Features
 
-- **ACID Transaction Hardening**: Enforces sequential consistency under race conditions using database-level pessimistic locking (`SELECT FOR UPDATE`).
-- **Distributed Locking Coordination**: Integrates **Redis Redlock** (via Redisson) to synchronize distributed triggers across multi-instance deployments.
-- **JPA N+1 Resolution**: Avoids Hibernate lazy loading bottlenecks through explicit **Fetch Joins** and `@EntityGraph` definitions.
-- **REST API Versioning**: Implements strict URI version control (`/api/v1`) protecting endpoints from breaking changes.
-- **Gen-AI Spending Assistant**: Integrates **Spring AI** (Ollama / Groq / Gemini) to automatically categorize transactions and generate spend analysis.
-- **Durable Idempotency Engine**: Enforces exactly-once execution on mutation APIs via SHA-256 request payload hashing and persistent state checking.
-- **Transactional Outbox Pattern**: Guarantees atomic consistency between state transitions and event streaming without dual-write vulnerabilities.
-- **Pluggable Resilience Policies**: Configured via Resilience4j for client-side rate-limiting, exponential backoff retries with jitter, and call timeouts.
-- **Telemetry & Observability**: Integrated with Spring Boot Actuator, Prometheus metrics, Logback MDC-based distributed trace correlation, and Grafana dashboards.
+- **REST API**: Basic CRUD endpoints for User registration and Transaction creation.
+- **Layered Architecture**: Controller → Service → Repository pattern with Spring Data JPA.
+- **In-Memory Database**: H2 with auto-generated schema for zero-dependency local development.
+- **Code Quality**: Spotless (Eclipse formatter) + Checkstyle enforced at Maven `validate` phase.
+- **CI Pipeline**: GitHub Actions workflow running `mvn clean verify` on push/PR to `main`.
+- **Actuator**: Health, info, and metrics endpoints exposed.
 
 ---
 
-## Project Documentation Directory
+## Target Architecture (Roadmap)
 
-1. 📘 **[System Architecture Guide](docs/ARCHITECTURE.md)**: Deep technical details on topology, locking, idempotency, Spring profiles, and observability.
-2. 🗓️ **[Phased Implementation Roadmap](docs/ROADMAP.md)**: Subdivided step-by-step phases (A and B) spanning database migrations, security, event streaming, and deployment.
-3. 🌐 **[REST API Specification](docs/API_SPECIFICATION.md)**: Complete request and response payload schemas, versioned endpoints, validations, status codes, and RFC 7807 error formats.
-4. 📋 **[Engineering Conventions](docs/CONVENTIONS.md)**: Coding standards, Git commit conventions, PR guidelines, and test naming rules.
-5. 📜 **[Architecture Decision Records](docs/ADR.md)**: Log of architectural decisions, context, trade-offs, and consequences.
+The following features are planned and will be implemented across future phases:
 
----
+- ACID transaction hardening with pessimistic locking and deadlock avoidance
+- Balance ledger with double-entry bookkeeping for auditability
+- DTO layer with input validation and RFC 7807 error responses
+- PostgreSQL with Flyway-managed schema migrations
+- Durable idempotency engine with SHA-256 payload hashing
+- Transactional outbox pattern for reliable event streaming
+- JWT authentication and authorization
+- Resilience4j fault tolerance (rate limiting, retry, circuit breaker)
+- Redis caching and distributed locking
+- Kafka event streaming
+- Structured logging with MDC trace correlation and Prometheus metrics
+- Multi-stage Docker build with full-stack Docker Compose
+- Kubernetes manifests with health probes and graceful shutdown
+- Gen-AI spend insights with Spring AI
 
-## Spring Profiles Strategy
+See **[System Architecture Guide](docs/ARCHITECTURE.md)** for detailed design documentation.
 
-The application leverages profile isolation to adapt resources to the target environment dynamically:
+---
 
-- **`local` (Default)**: In-memory H2 database, automated hibernate schema updates, and zero-dependency local startup.
-- **`test`**: Active during integration tests, utilizing **Testcontainers** to dynamically boot local Postgres/Kafka container instances for validation.
-- **`prod`**: Production-grade settings. Database credentials and broker addresses are read from system environment variables. Schema evolution is strictly managed by **Flyway migrations**.
-- **`prod-light` (Resource Constrained / Free Tier)**: Memory-optimized profile for single constrained virtual servers (1 GiB RAM). Uses lightweight in-memory fallbacks for Redis and Kafka to prevent OOM failures.
+## Project Documentation
+
+| Doc | Description |
+|-----|-------------|
+| 📘 [System Architecture](docs/ARCHITECTURE.md) | Design patterns, concurrency control, observability |
+| 🗓️ [Phased Roadmap](docs/ROADMAP.md) | Step-by-step evolution plan |
+| 🌐 [API Specification](docs/API_SPECIFICATION.md) | Endpoints, payloads, validation rules, error formats |
+| 📋 [Conventions](docs/CONVENTIONS.md) | Coding standards, Git workflow, testing rules |
+| 📜 [Architecture Decisions](docs/ADR.md) | Decision records with context and trade-offs |
 
 ---
 
 ## Quick Start
 
-### 1. Build and Run Local Tests
-Requires JDK 25 and Maven:
-```bash
-mvn clean install
-mvn test
-```
+### Prerequisites
+- JDK 25 (Temurin recommended)
+- Maven 3.9+
 
-### 2. Local Standalone Startup (Zero Dependencies)
-Boots the application on port `8080` using H2 in-memory storage:
+### Build & Run
 ```bash
-mvn spring-boot:run
-```
-- **H2 Console**: Available at `http://localhost:8080/h2-console`
-  - *JDBC URL*: `jdbc:h2:mem:payupidb`
-  - *Credentials*: `user` / `user`
+# Build and run tests
+mvn clean verify
 
-### 3. Local Full-Stack Ecosystem Startup (Docker Compose)
-To run a local staging environment containing Postgres, Redis, Kafka KRaft, Prometheus, and Grafana:
-```bash
-docker-compose up --build
+# Start locally (H2 in-memory, port 8080)
+mvn spring-boot:run
 ```
 
----
+- **H2 Console**: `http://localhost:8080/h2-console`
+  - JDBC URL: `jdbc:h2:mem:payupidb`
+  - Credentials: `user` / `user`
 
-## Production Deployment Readiness
-
-### Kubernetes Deployment
-Static Kubernetes manifests are defined under the `k8s/` directory. Deploy using:
+### Docker
 ```bash
-kubectl apply -f k8s/
-```
-- **Liveness Probe**: Routed to `/actuator/health/liveness`
-- **Readiness Probe**: Routed to `/actuator/health/readiness`
-- **Graceful Shutdown**: Handled via `server.shutdown=graceful` coordinating with container orchestration to process in-flight transactions before pod termination.
-
-### GraalVM Native Compilation
-To compile the application to a lightweight, platform-native binary that starts in milliseconds and consumes ~30-50MB of RAM:
-```bash
-# Compile native binary locally
-mvn -Pnative native:compile
-
-# Or build an optimized native OCI image via Buildpacks
-mvn -Pnative spring-boot:build-image
+docker-compose up --build
 ```
 
 ---
Original file line number	Diff line number	Diff line change
Expand Up		@@ -37,3 +37,4 @@ build/

		### Internal docs (not committed) ###
		internal/
		internal/*