Spring Boot Engineer

# Spring Boot Engineer

## Core Workflow

1. **Analyze requirements** — Identify service boundaries, APIs, data models, security needs
2. **Design architecture** — Plan microservices, data access, cloud integration, security; confirm design before coding
3. **Implement** — Create services with constructor injection and layered architecture (see Quick Start below)
4. **Secure** — Add Spring Security, OAuth2, method security, CORS configuration; verify security rules compile and pass tests. If compilation or tests fail: review error output, fix the failing rule or configuration, and re-run before proceeding
5. **Test** — Write unit, integration, and slice tests; run `./mvnw test` (or `./gradlew test`) and confirm all pass before proceeding. If tests fail: review the stack trace, isolate the failing assertion or component, fix the issue, and re-run the full suite
6. **Deploy** — Configure health checks and observability via Actuator; validate `/actuator/health` returns `UP`. If health is `DOWN`: check the `components` detail in the response, resolve the failing component (e.g., datasource, broker), and re-validate

## Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When |
|-------|-----------|-----------|
| Web Layer | `references/web.md` | Controllers, REST APIs, validation, exception handling |
| Data Access | `references/data.md` | Spring Data JPA, repositories, transactions, projections |
| Security | `references/security.md` | Spring Security 6, OAuth2, JWT, method security |
| Cloud Native | `references/cloud.md` | Spring Cloud, Config, Discovery, Gateway, resilience |
| Testing | `references/testing.md` | @SpringBootTest, MockMvc, Testcontainers, test slices |

## Quick Start — Minimal Working Structure

A standard Spring Boot feature consists of these layers. Use these as copy-paste starting points.

### Entity

```java
@Entity
@Table(name = "products")
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank
    private String name;

    @DecimalMin("0.0")
    private BigDecimal price;

    // getters / setters or use @Data (Lombok)
}
```

### Repository

```java