Cursor-rules-java 301-frameworks-spring-boot-core

Use when you need to review, improve, or build Spring Boot 4.0.x applications — including proper usage of @SpringBootApplication, component annotations (@Controller, @Service, @Repository), bean definition and scoping, configuration classes and @ConfigurationProperties (with @Validated), component scanning, conditional configuration and profiles, constructor injection, @Primary and @Qualifier for multiple beans of the same type, bean minimization, graceful shutdown, virtual threads, Jakarta EE namespace consistency, and scheduled tasks. Part of the skills-for-java project

install

source · Clone the upstream repo

git clone https://github.com/jabrena/cursor-rules-java

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/jabrena/cursor-rules-java "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/301-frameworks-spring-boot-core" ~/.claude/skills/jabrena-cursor-rules-java-301-frameworks-spring-boot-core && rm -rf "$T"

manifest: skills/301-frameworks-spring-boot-core/SKILL.md

Spring Boot Core Guidelines

Apply Spring Boot Core guidelines for annotations, bean management, configuration, and dependency injection.

What is covered in this Skill?

@SpringBootApplication and main application class
Component annotations: @RestController, @Service, @Repository
Bean definition, scoping, lifecycle
Configuration classes and @ConfigurationProperties (with @Validated for fail-fast startup)
Component scanning and package organization
Conditional configuration and profiles (@Profile, @ConditionalOn*)
Constructor dependency injection
@Primary and @Qualifier for disambiguation when multiple beans share a type
Bean minimization and composition
Graceful shutdown for in-flight work
Virtual threads on supported stacks for concurrency-bound workloads
Jakarta EE namespace consistency (jakarta.* preferred; avoid mixing legacy javax.annotation / javax.validation)
Scheduled tasks and background processing

Scope: Apply recommendations based on the reference rules and good/bad code examples.

Constraints

Before applying any Spring Boot changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification.

MANDATORY: Run
```
./mvnw compile
```
or
```
mvn compile
```
before applying any change
SAFETY: If compilation fails, stop immediately — compilation failure is a blocking condition
VERIFY: Run
```
./mvnw clean verify
```
or
```
mvn clean verify
```
after applying improvements
BEFORE APPLYING: Read the reference for detailed rules, good/bad patterns, and constraints

When to use this skill

Review Java code for Spring Boot application
Apply best practices for Spring Boot application in Java code

Reference

For detailed guidance, examples, and constraints, see references/301-frameworks-spring-boot-core.md.