Refactor Clean Skill

Activation Timing

• User requests dead code cleanup
• Code maintenance and optimization
• Remove unused code

Step 1: Detect Dead Code

mvn dependency:analyze

mvn spotbugs:check

mvn pmd:check

mvn test jacoco:report

mvn checkstyle:check

# Find class definitions, then check if they are referenced
grep -r "ClassName" --include="*.java" | grep -v "ClassName.java"

Step 2: Classify Detection Results

Step 3: Secure Deletion Cycle

1. Run the full test suite — Establish a baseline (all tests pass)
   bash

   mvn clean test

2. Delete dead code — Use editing tools for precise removal
3. Re-run tests — Verify no functionality is broken
   bash

   mvn test

4. If tests fail — Roll back immediately with

   git checkout -- <file>

   and skip this item
5. If tests pass — Proceed to the next item

Step 4: Process Caution Required Level Items

• Search for dynamic calls: Reflection

  Class.forName()

  ,

  Method.invoke()

• Search for string references: Class names in configuration files, Spring Bean names
• Check if they are exported by Feign interfaces
• Check if there are corresponding Req/Resp/Query object references in the api module
• Verify no other microservice calls exist (check api module interfaces)

Step 5: Merge Duplicate Code

• Similar methods (>80% similarity) — Merge into one
• Duplicate DTO conversion logic — Use MapStruct or extract utility methods
• Valueless wrapper methods — Use direct inline calls
• Redundant middle layers — Remove unnecessary delegates

Step 6: Summary

Dead Code Cleanup Report
──────────────────────────────
Deleted:   12 unused methods
          3 unused classes
          5 unused dependencies
Skipped:   2 items (test failed)
Saved:     Approximately 450 lines of code
──────────────────────────────
Compilation passed ✅
Test passed ✅
Coverage: 85% ✅

Java Web Project Specific Rules

Prohibited Deletions

• Feign interfaces in api modules — May be called by other microservices
• Entity classes — Dynamically used by MyBatis-Plus
• Enum classes (suffixed with Enum) — May be used for serialization/deserialization
• Mapper interfaces — SQL in XML may make dynamic calls
• Spring configuration classes — Affect application startup

Layered Architecture Check

# Controller cannot directly call Mapper
grep -r "Mapper" --include="*Controller.java" | grep -v "//"

# Service layer is prohibited from directly using QueryWrapper
grep -r "QueryWrapper\|LambdaQueryWrapper" --include="*ServiceImpl.java"

Maven Dependency Cleanup

# Analyze unused dependencies
mvn dependency:analyze

# Pay attention to the output:
# - Unused declared dependencies: Can be safely removed
# - Used undeclared dependencies: Need to be explicitly declared

Core Rules

• Prohibit deletion without running tests first
• Delete only one item at a time — Atomic changes make rollback easier
• Skip if uncertain — Keeping dead code is better than breaking the production environment
• Separate cleanup and refactoring — Clean up first, then refactor
• Compile and verify after each batch —

  mvn compile