| name | java-spring-boot-coldstart |
| description | Bootstrap and build Java 21 Spring Boot 3 services for a team with mixed Java experience. Covers REST APIs, SQS messaging via Spring Cloud AWS, Spring Security 6 (JWT resource server), and JUnit 5 + Mockito testing. Maven, no Lombok. Use when creating a new Spring Boot project, adding REST endpoints/SQS listeners/security config, or writing tests against Spring components. |
Java Spring Boot
Java 21, Spring Boot 3.x, Maven, JUnit 5 + Mockito, no Lombok.
When the user wants a new project
Run the bootstrap script. It calls Spring Initializr with the team's defaults baked in (Java 21, Maven, Boot 3.3.5, web + validation + security + oauth2-resource-server + actuator + configuration-processor + testcontainers).
scripts/new_project.sh <artifact-id> [group-id] [output-dir]
After it runs, follow up with whatever the project actually needs:
- SQS — add
spring-cloud-aws-starter-sqs and BOM (sqs.md). Initializr does not include this.
- Persistence — add
spring-boot-starter-data-jpa + a driver. (Not covered in detail by this skill — ask the user about their DB choice.)
- Lombok — don't, see conventions.md. Plant the seed; don't fight a lost battle.
When the user wants to add/modify code in an existing project
Read the relevant reference file before writing code. Each one is short and focused:
| What you're working on | Read |
|---|
| REST controllers, DTOs, validation, error handling | rest.md |
| SQS producers, listeners, DLQs, LocalStack | sqs.md |
| Auth filter chain, JWT, scopes, method security, CORS | security.md |
| JUnit 5, Mockito, MockMvc, slice tests, Testcontainers | testing.md |
| Project layout, DI, records, config props, Java 21 features | conventions.md |
If a task spans multiple areas (e.g. "add a secured endpoint that publishes to SQS") read each relevant file — don't try to remember.
Audience
This skill is for a team with mixed Java experience. When explaining choices, briefly say why — especially when the modern Spring Boot 3 / Java 21 idiom diverges from older patterns the team may remember (WebSecurityConfigurerAdapter, javax.*, field injection, manual constructors instead of records). The reference files do this; carry the same tone into the code you write.
Non-goals
- Reactive (WebFlux) — out of scope. Use Spring MVC.
- Kotlin — out of scope. Java only.
- Microservice patterns (service discovery, config server, gateway) — not covered. Add explicitly when needed.
