Dr Jskill

Spring Boot skill that follows Julien Dubois' best practices.

Overview

This agent skill helps you create Spring Boot projects following Julien Dubois' best practices. It provides tools and scripts to quickly bootstrap Spring Boot applications using https://start.spring.io.

Recommended model: Dr JSkill works best with GPT-5.5.

Version Management

Centralized versions live in versions.json. All scripts read from it via scripts/lib/versions.mjs (JavaScript). Update this file to bump Java, Spring Boot fallback, Postgres, Node/npm, Testcontainers, etc.

Prerequisites

1. Java 25 installed
2. Node.js 24.x and NPM 11.x (for front-end development)
3. Docker installed and running

Capabilities

• Generate Spring Boot projects with predefined configurations
• Support for various Spring Boot versions and dependencies
• Follow best practices for project structure and configuration
• Quick setup scripts for common use cases
• Docker support for containerized deployments
• Front-end development with multiple framework options:
  • Vue.js 3 (default) - Progressive framework with Composition API
  • React 19 - Popular library for building user interfaces
  • Angular 22 - Full-featured framework with TypeScript
  • Vanilla JavaScript - No framework, pure ES6+ with Vite

Usage

Using the Scripts

This skill includes cross-platform JavaScript (Node.js) scripts in the scripts/ directory that can be used to download pre-configured Spring Boot projects from start.spring.io. They work on Linux, macOS, and Windows.

Unified launcher (cross-platform):

node scripts/create-project my-app com.myco my-app com.myco.myapp 25 fullstack --output-dir /absolute/path/to/user/workspace

Direct invocation:

node scripts/create-project-latest.mjs my-app com.myco my-app com.myco.myapp 25 fullstack --output-dir /absolute/path/to/user/workspace

Flags supported:

• --boot-version <x.y.z> / -BootVersion: override Spring Boot version
• --project-type basic|web|fullstack / -ProjectType
• --output-dir <absolute-path>: create the generated project folder under this directory

Output directory rule (important for Agent Skills): bundled scripts are run from the skill directory root. When the user asks to create an app, pass --output-dir with the user's current working directory from the agent session so the generated project folder is created in the user's workspace, not inside the dr-jskill skill folder. Only omit --output-dir when running Dr JSkill's own tests, where generating inside the skill checkout is intentional.

Tip: The create-project-latest script auto-resolves preferred Boot 4.x and falls back to the configured springBootFallback if 4.x is not yet available. Override with --boot-version if needed.

Latest Version Project ⭐

Use the create-project-latest.mjs script to create a project with the latest Spring Boot version (automatically fetched):

node scripts/create-project-latest.mjs my-app com.mycompany my-app com.mycompany.myapp 25 web

Project types available:

• basic - Minimal Spring Boot project
• web - Web application with REST API capabilities
• fullstack - Complete application with database and security

Basic Spring Boot Project

Use the create-basic-project.mjs script to create a basic Spring Boot project with essential dependencies:

node scripts/create-basic-project.mjs

Web Application

Use the create-web-project.mjs script to create a Spring Boot web application with web dependencies:

node scripts/create-web-project.mjs

Full-Stack Application

Use the create-fullstack-project.mjs script to create a comprehensive Spring Boot application with database, security, and web dependencies:

node scripts/create-fullstack-project.mjs

Best Practices

When creating Spring Boot projects:

1. Use the latest Spring Boot version (currently 4.x) - the create-project-latest.mjs script automatically fetches it
2. Review Spring Boot 4 critical considerations: See Spring Boot 4 Migration Guide for Jackson 3 annotations and TestContainers configuration
3. Include Spring Boot Actuator for production-ready features
4. Use Spring Data JPA for database access
5. Use PostgreSQL for database - see Database Best Practices for optimization
6. Use properties files for configuration - see Configuration Best Practices
7. Set up foundational dotfiles: .gitignore, .env.sample, .editorconfig, .gitattributes, .dockerignore, optional .vscode/, .devcontainer/ - see Project Setup & Dotfiles
   • The .env file is the canonical location for local secrets; instruct users to copy .env.sample → .env and fill in real values
   • NEVER read or expose .env: it contains real secrets — do not cat, view, or print its contents; only .env.sample (placeholder values) may be read or displayed
8. Follow daily Git best practices for small branches, reviewed diffs, safe commits, pull requests, and worktrees - see Git Best Practices
9. Use spring-boot-docker-compose for automatic database startup during development - see Docker Guide
10. Follow RESTful API design principles
11. Configure proper logging with Logback - see Logging Best Practices
12. Use Maven for dependency management
13. Include Spring Boot DevTools for development productivity
14. Add Spring Security only when needed - see Security Guide for best practices
15. Configure Docker for containerized deployments - see Docker Guide
16. Enable GraalVM native image support for faster startup - see GraalVM Guide
17. Always ship a startup banner that prints access URLs when the app is ready - see Startup Banner
18. The user must review changes before they are committed to git. Ask the user before initializing a Git repository, or running git commands.

Java Code Intelligence (JDTLS) ⭐

Generated projects integrate with the Eclipse JDT Language Server (JDTLS) so AI agents can navigate, refactor, and diagnose Java code semantically rather than with text search. The scripts ship a .github/lsp.json that wires JDTLS into GitHub Copilot CLI automatically.

For the AI agent: when working on Java files, prefer the lsp tool over grep/view/sed. It understands imports, generics, inheritance, and Javadoc.

Preference order for Java work: lsp → grep with .java glob → view.

Install JDTLS once: brew install jdtls (or see JDTLS guide for other platforms). Full setup, gotchas, and editor integrations live in references/JDTLS.md.

Project Structure

The service layer is only included if it adds value (e.g. complex business logic). For simple CRUD applications, the controller can directly call the repository.

Generated projects follow the following recommended structure:

my-spring-boot-app/
├── .gitignore                 # Java + front-end + secrets (see references/PROJECT-SETUP.md)
├── .env.sample                # Template for local env vars; .env is gitignored
├── .editorconfig              # Consistent formatting across IDEs
├── .gitattributes             # Normalize line endings, better diffs
├── .dockerignore              # Slim Docker build contexts
├── .vscode/                   # Optional editor recommendations
│   ├── extensions.json
│   └── settings.json
├── .devcontainer/             # Optional Dev Container (Java 25 + Node 24 + PostgreSQL)
│   ├── devcontainer.json
│   └── docker-compose.yml
├── src/
│   ├── main/
│   │   ├── java/
│   │   │   └── com/example/app/
│   │   │       ├── Application.java
│   │   │       ├── config/
│   │   │       ├── controller/
│   │   │       ├── service/         # Only included if needed
│   │   │       ├── repository/
│   │   │       └── domain/
│   │   └── resources/
│   │       ├── static/              # Front-end web assets (HTML, CSS, JS)
│   │       │   ├── index.html
│   │       │   ├── css/
│   │       │   │   └── styles.css
│   │       │   ├── js/
│   │       │   │   └── app.js
│   │       │   └── images/
│   │       └── application.properties
│   └── test/
│       └── java/
│           └── com/example/app/
│               ├── config/
│               ├── controller/
│               ├── service/         # Only included if needed
│               ├── repository/
│               └── domain/
├── Dockerfile                   # JVM image (jlink runtime + distroless)
├── Dockerfile-aot               # JVM + Spring AOT image
├── Dockerfile-native            # GraalVM native image
├── Dockerfile-crac              # CRaC (fast-restore) image
├── checkpoint-and-run.sh        # CRaC entrypoint helper
├── compose.yaml                 # Dev database (spring-boot-docker-compose)
├── docker-compose.yml           # Full stack with PostgreSQL (JVM)
├── docker-compose-aot.yml       # Full stack with PostgreSQL (AOT)
├── docker-compose-native.yml    # Full stack with PostgreSQL (native)
├── docker-compose-crac.yml      # CRaC app (database-free)
├── pom.xml
└── README.md

Dependencies

Generated projects include: Spring Web, Spring Data JPA, Spring Boot Actuator, DevTools, PostgreSQL, Validation, Docker Compose support, Test Starter with JUnit 5, and TestContainers.

Configuration

Use .properties files (not YAML), externalize secrets via environment variables, and leverage @ConfigurationProperties for type safety. See the Configuration Guide for profiles, secrets management, and common patterns.

The .env file is the single local secret store — never read or print it; only .env.sample (placeholder values) may be shown.

For database optimization, see the Database Best Practices Guide.

Security (Optional)

Spring Security is optional - only add it when you need authentication or authorization. See the Security Guide for JWT, OAuth2, role-based access, and CORS configuration.

Testing

See the Testing Guide for unit tests (Mockito, @WebMvcTest), integration tests (TestContainers + @ServiceConnection), and Given-When-Then patterns with AssertJ.

Front-End Development

Choose a front-end framework:

• Vue.js 3 (default) ⭐ → Vue.js Guide
• React 19 → React Guide
• Angular 22 → Angular Guide
• Vanilla JavaScript (no framework) → Vanilla JS Guide

All options include: Vite/CLI dev server with hot reload, Bootstrap 5.3+, SPA routing, and automatic build into the Spring Boot JAR.

When wiring the frontend-maven-plugin, bind the Node install, npm install, and npm run build executions to the generate-resources phase. This makes ./mvnw spring-boot:run build the frontend before Spring Boot starts, instead of only building it during explicit package-oriented commands.

Non-interactive scaffolding (important for CI and AI agents). Two separate prompts must be silenced:

1. npm's own "Ok to proceed?" install prompt — silence by placing -y before the package name (flags after -- go to the scaffolder, not to npm). Use npm create -y vite@latest … or npx --yes create-vite@latest ….
2. The scaffolder's own prompts — create-vite 9.x and Angular CLI 22 still pose interactive questions (e.g. "Use rolldown-vite?", analytics opt-in) that -y / --yes do not silence. The reliable fix is to close stdin: pipe echo | into the command so the scaffolder immediately sees EOF and accepts defaults.

Canonical recipes:

• React / Vanilla: echo | npx --yes create-vite@latest frontend --template react (or --template vanilla)
• Vue: npm create -y vue@latest frontend -- --router --pinia --vitest --eslint --prettier (create-vue does not pose extra prompts)
• Angular: echo | npx --yes @angular/cli@22 new frontend --style=css --ssr=false --skip-git --defaults --skip-install, then npm install

Vue: normalize before the first npm install (required). create-vue scaffolds oxlint and eslint-plugin-oxlint pinned to mismatched minors, so npm install fails with an ERESOLVE peer conflict — which fails the frontend-maven-plugin step and therefore the whole Maven build. Immediately after scaffolding, run:

# Run from the Dr JSkill skill directory (that is where `scripts/` lives),
# passing the path to the generated project's frontend/ directory.
node scripts/normalize-vue-frontend.mjs /absolute/path/to/my-app/frontend

It drops the oxlint dual-linter, leaving the single ESLint pipeline, and adds the lint:check script that create-vue never emits but the Maven frontend-maven-plugin build runs. It is idempotent, and --check reports without writing. See Vue.js Guide.

Vitest + callback Vite config. If vite.config.js exports defineConfig(({ mode }) => ...), do not let the generated vitest.config.js call mergeConfig(viteConfig, ...). Resolve the callback first with viteConfig({ mode: 'test', command: 'serve' }); otherwise Vitest fails with Cannot merge config in form of callback. See Vue.js Guide.

Docker Deployment

Spring Boot automatically manages Docker containers during development via spring-boot-docker-compose. For production, pick one of the four provided images: Dockerfile (JVM, jlink + distroless), Dockerfile-aot (JVM + Spring AOT), Dockerfile-native (GraalVM native), or Dockerfile-crac (CRaC fast-restore). See the Docker Guide for full setup, the matching Maven profiles, and deployment patterns.

GraalVM Native Images

Build native images via Docker (no local GraalVM needed) or locally with ./mvnw -Pnative -DskipTests package native:compile. See the GraalVM Guide for configuration, runtime hints, testing, and CI/CD integration.

Azure Deployment

Deploy to Azure Container Apps with an optional VNET-injected Azure Database for PostgreSQL Flexible Server. Uses GitHub Container Registry (GHCR) for image storage (pushed via GITHUB_TOKEN in CI, pulled by Container Apps using a stored PAT) and Container Apps secrets for the DB password — no secrets in source, env dumps, or shell history. Includes a GitHub Actions OIDC workflow, and supports both the JVM and GraalVM native image variants. See the Azure Deployment Guide.

Validation

Run validation steps first. If anything fails, fix before proceeding.

Once the project is generated, go through the steps above to ensure that the generated project is fully functional and follows best practices. If any validation step fails, try to identify the issue and fix it before proceeding. This ensures that the generated project is of high quality and ready for development.

Additional Resources

Included Reference Guides

Core Spring Boot:

• Spring Boot 4 Migration Guide - Key changes from Spring Boot 3, Jackson 3 annotations
• Configuration Best Practices - Properties files, profiles, secrets management
• Logging Best Practices - Logback configuration and patterns
• Java Code Intelligence (JDTLS) - LSP-based navigation, refactoring, diagnostics

Data and Persistence:

• Database Best Practices - PostgreSQL and Hibernate optimization

Security (Optional):

• Security Guide - Spring Security, JWT, OAuth2, authentication patterns

Testing:

• Testing Guide - Unit and integration testing with TestContainers

Front-End Development:

• Vue.js Development Guide - Vue.js 3 with Vite (default)
• React Development Guide - React 19 with Vite
• Angular Development Guide - Angular 22 with Angular CLI
• Vanilla JS Development Guide - Pure ES6+ with Vite

Project Setup:

• Project Setup & Dotfiles - .gitignore, .env.sample, .editorconfig, .gitattributes, .dockerignore, .devcontainer/
• Git Best Practices - daily Git workflow, branches, commits, pull requests, safe undo, stashing, and worktrees

Deployment:

• Docker Deployment Guide - Docker, Docker Compose, development automation
• GraalVM Native Images Guide - Docker-based native builds, optimization
• Azure Deployment Guide - Azure Container Apps, PostgreSQL Flexible Server, GitHub Container Registry (GHCR) image push/pull, Container Apps secrets for DB password, GitHub Actions OIDC