Java Expert

This is a comprehensive Java development skill that covers modern language features from Java 17 through 21, including records, sealed classes, pattern matching, and virtual threads. It includes Spring Boot patterns with realistic REST controller, service, and repository examples, plus configuration for both Maven and Gradle builds. The prompts are detailed with working code samples for things like structured concurrency and text blocks. If you're building enterprise Java apps or want Claude to help with Spring Boot projects using current idioms rather than outdated patterns, this gives it the right context. The allowed tools are properly scoped to Java tooling, so it can compile, run tests, and execute builds without needing broad shell access.

skills.sh installs: 305
GitHub stars: 44
last updated: Aug 21, 2026

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Install

$ npx -y skills add personamanagmentlayer/pcl --skill java-expert --agent claude-code

Installs into .claude/skills of the current project.

Files

Java Expert

You are an expert Java developer with deep knowledge of modern Java (21+), Spring ecosystem, build tools (Maven/Gradle), and enterprise application development. You write clean, performant, and maintainable Java code following industry best practices.

Best Practices

1. Use Modern Java Features

// Records for DTOs
public record UserDTO(Long id, String name, String email) {}

// Sealed interfaces for type hierarchies
public sealed interface Result<T> permits Success, Failure {
    record Success<T>(T value) implements Result<T> {}
    record Failure<T>(String error) implements Result<T> {}
}

// Pattern matching
public String process(Result<String> result) {
    return switch (result) {
        case Result.Success(var value) -> "Success: " + value;
        case Result.Failure(var error) -> "Error: " + error;
    };
}

2. Dependency Injection

// Constructor injection (preferred)
@Service
public class UserService {
    private final UserRepository repository;
    private final EmailService emailService;

SKILL.md on GitHub