Java Expert

What it does

This skill provides expert guidance and code generation related to modern Java development practices, specifically focusing on backend systems. It covers key features introduced in recent Java versions (Java 21+) and Spring Boot 3.x, including Virtual Threads (Project Loom), Pattern Matching, Records, and Sealed Classes. The skill aims to help developers build robust, scalable, and maintainable applications by leveraging these advanced capabilities.

When to use it

• You're migrating an I/O-bound application and want to improve scalability using Virtual Threads.
• You’re working with Java 21+ and want to utilize pattern matching for cleaner code.
• You need assistance creating immutable data carriers (Records) with automatic getter and toString() methods.
• You're designing a system where you need to restrict class extensions or ensure exhaustive pattern matching using Sealed Classes.
• You are setting up a new Spring Boot 3.x project and want guidance on best practices for framework setup and layered architecture.

Key capabilities

• Virtual Threads (Project Loom): Guidance on implementation and configuration, including thread pool creation (Executors.newVirtualThreadPerTaskExecutor()).
• Pattern Matching: Demonstrates switch statements with pattern matching and record patterns.
• Records: Provides examples of creating immutable data carriers with automatically generated methods.
• Sealed Classes: Explains how to restrict class extensions and ensure exhaustive pattern matching.
• Spring Boot 3.x Best Practices: Offers advice on framework setup, project structure (layered architecture), controller layer design, and DTO usage.

Example prompts

• "Show me an example of using Virtual Threads in Spring Boot 3.2 to handle concurrent connections."
• "How can I use pattern matching with a switch statement in Java?"
• "Can you generate a Record data transfer object (DTO) for a User with name, email, and birthdate fields, including validation logic?"

Tips & gotchas

• Requires Java 21+ or Spring Boot 3.2+ to utilize all features effectively.
• Virtual Threads are particularly beneficial for I/O-bound tasks; they may not provide significant performance gains in CPU-intensive scenarios.
• Familiarity with basic Java and Spring Boot concepts is recommended for optimal use of this skill.