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
- EDGE CASE: If request scope is ambiguous, stop and ask a clarifying question before applying changes
- EDGE CASE: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance
When to use this skill
- Review Java code for Spring Boot application
- Apply best practices for Spring Boot application in Java code
Workflow
- Read reference and assess project context
Read references/301-frameworks-spring-boot-core.md and inspect the current project setup before proposing changes.
- Gather scope and decide target improvements
Identify requested outcomes, constraints, and the minimum safe set of changes to apply.
- Apply framework-aligned changes
Implement or refactor configuration/code following the reference patterns and project conventions.
- Run verification and report results
Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions.
Reference
For detailed guidance, examples, and constraints, see references/301-frameworks-spring-boot-core.md.
1---2name: 301-frameworks-spring-boot-core3description: 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. This should trigger for requests such as Review Java code for Spring Boot application; Apply best practices for Spring Boot application in Java code. Part of cursor-rules-java project4license: Apache-2.05---6# Spring Boot Core Guidelines
7
8Apply Spring Boot Core guidelines for annotations, bean management, configuration, and dependency injection.
9
10**What is covered in this Skill?**
11
12- @SpringBootApplication and main application class
13- Component annotations: @RestController, @Service, @Repository
14- Bean definition, scoping, lifecycle
15- Configuration classes and @ConfigurationProperties (with @Validated for fail-fast startup)
16- Component scanning and package organization
17- Conditional configuration and profiles (@Profile, @ConditionalOn*)
18- Constructor dependency injection
19- @Primary and @Qualifier for disambiguation when multiple beans share a type
20- Bean minimization and composition
21- Graceful shutdown for in-flight work
22- Virtual threads on supported stacks for concurrency-bound workloads
23- Jakarta EE namespace consistency (jakarta.* preferred; avoid mixing legacy javax.annotation / javax.validation)
24- Scheduled tasks and background processing
25
26**Scope:** Apply recommendations based on the reference rules and good/bad code examples.
27
28## Constraints
29
30Before applying any Spring Boot changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification.
31
32- **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change
33- **SAFETY**: If compilation fails, stop immediately — compilation failure is a blocking condition
34- **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements
35- **BEFORE APPLYING**: Read the reference for detailed rules, good/bad patterns, and constraints
36- **EDGE CASE**: If request scope is ambiguous, stop and ask a clarifying question before applying changes
37- **EDGE CASE**: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance
38
39## When to use this skill
40
41- Review Java code for Spring Boot application
42- Apply best practices for Spring Boot application in Java code
43
44## Workflow
45
461. **Read reference and assess project context**
47
48Read `references/301-frameworks-spring-boot-core.md` and inspect the current project setup before proposing changes.
49
502. **Gather scope and decide target improvements**
51
52Identify requested outcomes, constraints, and the minimum safe set of changes to apply.
53
543. **Apply framework-aligned changes**
55
56Implement or refactor configuration/code following the reference patterns and project conventions.
57
584. **Run verification and report results**
59
60Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions.
61
62## Reference
63
64For detailed guidance, examples, and constraints, see [references/301-frameworks-spring-boot-core.md](references/301-frameworks-spring-boot-core.md).
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