Skill · spring-boot/spring-boot-4 · v1.0.0 · MIT
Spring Boot 4 Web Services
Spring Boot 4.1 REST services done right, and Boot 3.5 upgrades that keep the JSON contract, checked against Boot 4.1.2.
Teaches an agent the parts of Spring Boot 4 (4.1.2, Spring Framework 7.0.10, Jackson 3.1.7) that agents trained on Boot 2 and 3 get wrong when they build or upgrade Spring MVC services: the split starters and test starters, Jackson 3 packages and APIs (@JacksonComponent, ValueSerializer, JsonMapperBuilderCustomizer), the ObjectMapper bean that Boot 4 silently ignores, Jackson 3 default changes that alter the wire format without a compile error (enums read and written with toString, rejected missing primitives, sorted properties), built-in method validation versus a class-level @Validated, HandlerMethodValidationException and RFC 9457 problem details with per-field errors, the new test packages (@MockitoBean, RestTestClient, TestRestTemplate opt-in), RestTemplateBuilder and HTTP client property moves, HTTP service client groups, API versioning, core @Retryable and virtual threads. Every behaviour claim was measured on Boot 4.1.2.
- Backend
- API design
- Migration
- Testing
- build
- test
- maintain
- spring-boot
- java
- jvm
- junit
uplift
No runs exist for this digest.
Not measured for this digest.
Untested is not the same as useless: nobody has measured it yet. Proof comes from A/B runs on hidden tests:
npx sigil prove catalog/skills/spring-boot/spring-boot-4 --suite <suite> --runs 6trust level · submitted
- in the catalog: met
- structure check: not met
- static scan, no high findings: not met
- canary sandbox passed: not met
- maintainer approved: not met
canary sandbox
Not run for this digest.
static scan
Not run for this digest.
compatibility · targeted, compiled and evaluated are separate claims
| agent | targeted by author | compiled | evaluated in the lab | notes |
|---|---|---|---|---|
| Claude Code | targeted: yes | no record for compiled | no record for evaluated | |
| Codex | targeted: yes | no record for compiled | no record for evaluated | |
| Cursor | targeted: yes | no record for compiled | no record for evaluated | |
| GitHub Copilot | targeted: yes | no record for compiled | no record for evaluated | |
| Gemini CLI | targeted: yes | no record for compiled | no record for evaluated | |
| OpenCode | targeted: yes | no record for compiled | no record for evaluated |
declared permissions
- network
- none
- shell
- mvn, gradlew, javap, unzip, grep, ls
- filesystem
- write
- env
- none
Undeclared access is a finding in the scan and a tripwire in the canary.
source
- path
- catalog/skills/spring-boot/spring-boot-4
- authors
- dgesteves
- entry
- SKILL.md (agent-skill)
- registry
- 2026-11-02 · 5cb851d
install
$ npx sigil add spring-boot/spring-boot-4 --agent claude-codeNo compile record for Claude Code on this digest. Install never runs capability scripts, and refuses on any digest mismatch.
known limitations
- Written and measured against Spring Boot 4.1.2 (Framework 7.0.10, Jackson 3.1.7). 4.0.x behaves the same for everything here except where noted; check the release notes for 4.2 and later.
- Covers Spring MVC on the servlet stack. WebFlux, Spring Security 7, Spring Data and messaging are only touched where they meet the upgrade checklist.
- Jackson default changes are listed for the JSON features a REST API typically exercises; formats like XML, CBOR and Smile and polymorphic typing are not covered.
- The proof suite builds with Maven offline in a container. Gradle is mentioned for commands only.
- The suite measures behaviour through MockMvc and real HTTP in tests; production concerns like observability and native images are out of scope.