Java Cleanup

Java Code Cleanup

Systematically identify and remove dead code, update deprecated APIs, and apply modern Java patterns to maintain a clean, maintainable codebase.

When to Use This Skill

Use this skill when you need to:

• Remove unused imports and dead code
• Update deprecated API usage
• Apply modern Java features (8+)
• Fix Checkstyle/PMD issues
• Clean up before code review

Trigger phrases: "cleanup Java", "remove dead code Java", "modernize Java", "fix Checkstyle", "Java refactor"

What This Skill Does

Cleanup Areas

1. Dead Code Removal

   • Unused imports
   • Unused private methods
   • Unreachable code
   • Redundant code

2. Style Compliance

   • Checkstyle rules
   • PMD/SpotBugs
   • Naming conventions

3. Modernization

   • Streams API
   • Optional
   • var keyword
   • Records (Java 14+)

Instructions

Step 1: Run Analysis Tools

# Run Checkstyle
mvn checkstyle:check

# Run PMD
mvn pmd:check

# Run SpotBugs
mvn spotbugs:check

Step 2: Modernize Patterns

// Traditional loop → Stream
// Before
List<String> names = new ArrayList<>();
for (User user : users) {
    if (user.isActive()) {
        names.add(user.getName());
    }
}
// After
List<String> names = users.stream()
    .filter(User::isActive)
    .map(User::getName)
    .collect(Collectors.toList());

// Null checks → Optional
// Before
String name = user != null ? user.getName() : "Unknown";
// After
String name = Optional.ofNullable(user)
    .map(User::getName)
    .orElse("Unknown");

// Anonymous class → Lambda
// Before
button.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        handleClick(e);
    }
});
// After
button.addActionListener(e -> handleClick(e));

// Data class → Record (Java 14+)
// Before
public class User {
    private final String name;
    private final String email;
    // constructor, getters, equals, hashCode, toString
}
// After
public record User(String name, String email) {}

Tools

• Checkstyle: Style checking
• PMD: Static analysis
• SpotBugs: Bug detection
• IntelliJ Inspections: IDE analysis

Quality Checklist

• Unused imports removed
• Deprecated APIs updated
• Modern patterns applied
• Checkstyle passes
• Tests still pass

Related Skills

• code-review-quality - Code quality assessment

Version: 1.0.0 Last Updated: December 2025 Based on: AI Templates code_cleanup/java_cleanup.md

Iterative Refinement Strategy

This skill is optimized for an iterative approach:

1. Execute: Perform the core steps defined above.
2. Review: Critically analyze the output (coverage, quality, completeness).
3. Refine: If targets aren't met, repeat the specific implementation steps with improved context.
4. Loop: Continue until the definition of done is satisfied.