java-best-practice-checker
Expert Java code auditor for SE 8–24, flagging performance leaks, threading risks, and modernization gaps.
- Modernize legacy Java 8 code to use Records, Switch Expressions, and var.
- Identify thread-safety hazards and manual lock contention in concurrent code.
- Optimize String handling and Collection choices for high-throughput apps.
Free
One-time purchase
Included in download
- Downloadable skill package
- Works with Requires Java SE JDK
- 5 permissions declared
Sample Output
A real example of what this skill produces.
🔴 Issue 1 — Concatenation in loop (Report.build) Each += allocates a new String; O(n²) performance. // ✅ Fix StringBuilder sb = new StringBuilder(); for (var item : list) { sb.append(item); } return sb.toString();
| # | Location | Category | Issue | Severity | |---|---|---|---|---| | 1 | Report.build() | Strings | Loop concat | 🔴 High |
java-best-practice-checker
Expert Java code auditor for SE 8–24, flagging performance leaks, threading risks, and modernization gaps.
Free
One-time purchase
Included in download
- Downloadable skill package
- Works with Requires Java SE JDK
- 5 permissions declared
- Instant install
Sample Output
A real example of what this skill produces.
🔴 Issue 1 — Concatenation in loop (Report.build) Each += allocates a new String; O(n²) performance. // ✅ Fix StringBuilder sb = new StringBuilder(); for (var item : list) { sb.append(item); } return sb.toString();
| # | Location | Category | Issue | Severity | |---|---|---|---|---| | 1 | Report.build() | Strings | Loop concat | 🔴 High |
About This Skill
What it does
This skill performs an exhaustive, automated audit of Java source code ranging from SE 8 through the latest SE 24 features. It acts as a specialized static analysis engine that identifies violations of modern best practices, concurrency hazards, and architectural anti-patterns.
Why use this skill
Unlike standard linters, this skill provides deep context and "why it matters" explanations for every flag. It helps developers modernize legacy codebases by suggesting Java 21+ features like Record Patterns and Virtual Threads, while simultaneously catching classic "silent killers" like String Pool bypasses and thread-safety bugs in Singletons.
Supported areas
- Modern Syntax: Pattern matching (SE 21), Unnamed variables (SE 22), Stream Gatherers (SE 24).
- Core Performance: String handling, wrapper class caching, and JIT-friendly coding patterns.
- Collections: Deep analysis of the Collections Framework and the new SequencedCollection API.
- Architecture: Dependency injection, OOP encapsulation, and Design Pattern implementations.
- JVM Internals: Garbage collection awareness, memory leak detection, and resource management.
The Output
The skill generates a structured report featuring severity-coded issues (🔴/🟡/🟢), root-cause analysis, and side-by-side "Fix" code blocks. Every review concludes with a professional Summary Table for quick triage by lead developers or PR reviewers.
📖 Learn more: Best Code Review Skills for Claude Code →
Use Cases
- Modernize legacy Java 8 code to use Records, Switch Expressions, and var.
- Identify thread-safety hazards and manual lock contention in concurrent code.
- Optimize String handling and Collection choices for high-throughput apps.
- Ensure proper resource cleanup and prevent JVM memory leaks.
How to Install
mkdir -p ~/.claude/skills && curl -sL https://www.agensi.io/api/install/java-best-practice-checker | tar xz -C ~/.claude/skills/Free skills install directly. Paid skills require purchase - use the download button above after buying.
Reviews
Security Scanned
Passed automated security review
Permissions
Requires Java SE JDK