141-java-refactoring-with-modern-features
Modernizes Java code by applying Stream API, Optional, java.time, and modern language features.
Install
mkdir -p .claude/skills/141-java-refactoring-with-modern-features && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/16141" && unzip -o skill.zip -d .claude/skills/141-java-refactoring-with-modern-features && rm skill.zipInstalls to .claude/skills/141-java-refactoring-with-modern-features
Activation
This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.
Use when you need to refactor Java code to adopt modern Java features (Java 8+) — including migrating anonymous classes to lambdas, replacing Iterator loops with Stream API, adopting Optional for null safety, switching from legacy Date/Calendar to java.time, using collection factory methods, applying text blocks, var inference, or leveraging Java 25 features like flexible constructor bodies and module import declarations. This should trigger for requests such as Review Java code for modern Java development; Apply best practices for modern Java development in Java code. Part of cursor-rules-java projectKey capabilities
- →Migrate anonymous classes to lambda expressions
- →Replace Iterator loops with Stream API
- →Adopt Optional for null safety
- →Switch from legacy Date/Calendar to java.time
- →Use unmodifiable collection factory methods
- →Apply text blocks for multi-line strings
How it works
This skill identifies and applies modern Java (Java 8+) refactoring opportunities by replacing legacy idioms with contemporary features like lambdas, Stream API, and java.time, while ensuring compilation and verification.
Inputs & outputs
When to use 141-java-refactoring-with-modern-features
- →Refactor to Streams
- →Adopt Optional for null safety
- →Migrate to java.time
About this skill
Modern Java Development Guidelines (Java 8+)
Identify and apply modern Java (Java 8+) refactoring opportunities to improve readability, maintainability, and performance.
What is covered in this Skill?
- Lambda expressions and method references (over anonymous classes)
- Stream API for declarative collection processing
Optionalfor null-safe APIsjava.timeAPI (replacingDate/Calendar)- Default interface methods,
vartype inference - Unmodifiable collection factory methods (
List.of(),Set.of(),Map.of()) - Text blocks for multi-line strings
- Java 25 Flexible Constructor Bodies (JEP 513)
- Java 25 Module Import Declarations (JEP 511)
Scope: The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.
Constraints
Before applying any modern Java refactoring, ensure the project compiles. If compilation fails, stop immediately — do not proceed until the project compiles successfully. After applying improvements, run full verification.
- MANDATORY: Run
./mvnw compileormvn compilebefore applying any changes - SAFETY: If compilation fails, stop immediately — do not proceed until the project compiles successfully
- VERIFY: Run
./mvnw clean verifyormvn clean verifyafter applying improvements - BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each modern Java feature
- 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 modern Java development
- Apply best practices for modern Java development in Java code
- Modernize Java code with records pattern matching or switch expressions
- Replace legacy idioms with modern Java features
- Adopt Java 8+ language features safely
Workflow
- Compile project before modernization
Run ./mvnw compile or mvn compile and stop immediately if compilation fails.
- Read modern-Java reference and identify candidates
Read references/141-java-refactoring-with-modern-features.md and identify high-value opportunities to adopt modern Java features.
- Apply modern Java refactorings
Refactor incrementally using appropriate language/library features while preserving behavior and readability.
- Verify with full build
Run ./mvnw clean verify or mvn clean verify after applying improvements.
Reference
For detailed guidance, examples, and constraints, see references/141-java-refactoring-with-modern-features.md.
When not to use it
- →If the project does not compile before refactoring
- →If the request scope is ambiguous
- →If required inputs, files, or tooling are missing
Limitations
- →Requires the project to compile before applying changes
- →Requires full verification after applying improvements
- →Requires reading the reference for detailed examples and safeguards
How it compares
This skill systematically modernizes Java code by applying specific feature replacements, unlike a manual refactoring process that might miss opportunities or introduce errors.
Compared to similar skills
141-java-refactoring-with-modern-features side by side with the closest alternatives in the catalog.
| Skill | Installs | Updated | Safety | Difficulty |
|---|---|---|---|---|
| 141-java-refactoring-with-modern-features (this skill) | 0 | 2mo | No flags | Intermediate |
| jakarta-namespace | 2 | 6mo | Review | Intermediate |
| spring-boot-migration | 1 | 6mo | Review | Advanced |
| minecraft-bukkit-pro | 90 | 4mo | No flags | Advanced |
Try saying
Example prompts that trigger this skill in your AI assistant.
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