125-java-concurrency
Use when you need to apply Java concurrency best practices — including thread safety fundamentals, ExecutorService thread pool management, concurrent design patterns like Producer-Consumer, asynchronous programming with CompletableFuture, immutability and safe publication, deadlock avoidance, virtual threads, scoped values, backpressure, cancellation discipline, and observability for concurrent systems. Part of the skills-for-java project
74
67%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/125-java-concurrency/SKILL.mdQuality
Discovery
100%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a strong skill description that clearly defines its scope (Java concurrency best practices), lists numerous specific capabilities, and includes an explicit 'Use when' trigger clause. The only minor weakness is the use of second person 'you need to' rather than third person voice, and the trailing 'Part of the skills-for-java project' adds little selection value. The extensive list of concrete Java concurrency topics provides excellent trigger term coverage.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | The description lists many specific concrete capabilities: thread safety fundamentals, ExecutorService thread pool management, Producer-Consumer pattern, CompletableFuture, immutability and safe publication, deadlock avoidance, virtual threads, scoped values, backpressure, cancellation discipline, and observability. | 3 / 3 |
Completeness | The description explicitly starts with 'Use when you need to apply Java concurrency best practices' which clearly answers the 'when' question, and the extensive list of topics answers the 'what' question comprehensively. | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms a Java developer would use: 'thread safety', 'ExecutorService', 'thread pool', 'CompletableFuture', 'deadlock', 'virtual threads', 'Producer-Consumer', 'concurrency', 'backpressure'. These are all terms developers naturally use when seeking concurrency help. | 3 / 3 |
Distinctiveness Conflict Risk | The description is highly specific to Java concurrency, which is a clear niche. The combination of Java-specific terms (ExecutorService, CompletableFuture, virtual threads, scoped values) makes it very unlikely to conflict with other skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
35%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill is essentially a table of contents with a compilation gate and a pointer to a reference file. It lacks any concrete code examples, executable patterns, or actionable inline guidance — all substance is deferred to the reference. The constraints section is the strongest part, providing a clear compile/verify workflow, but the skill body itself gives Claude very little to act on without reading the external file.
Suggestions
Add at least 2-3 concrete before/after code examples inline (e.g., replacing synchronized HashMap with ConcurrentHashMap, or proper ExecutorService shutdown) so the skill has standalone actionable value.
Remove or drastically shorten the 'What is covered' bullet list — it reads like a syllabus and wastes tokens on information Claude doesn't need upfront.
Add a brief workflow for how to identify and fix concurrency issues: e.g., 1) scan for raw synchronized/Thread usage, 2) check for shared mutable state, 3) apply specific pattern from reference, 4) verify.
Include a minimal quick-start section with one complete, copy-paste-ready concurrency improvement example so the skill is useful even without consulting the reference file.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The 'What is covered' bullet list is essentially a table of contents that adds little actionable value — Claude doesn't need a preview of topics. However, the constraints section is reasonably tight and the file isn't excessively long. | 2 / 3 |
Actionability | The skill contains zero executable code examples, no concrete commands beyond compile/verify, and delegates all actual guidance to a reference file. It describes what to do abstractly ('apply recommendations based on applicable examples') rather than providing any concrete patterns or code. | 1 / 3 |
Workflow Clarity | There is a clear compile-before/verify-after sequence with an explicit blocking condition on compilation failure, which is good. However, the actual concurrency improvement workflow (how to identify issues, apply fixes, validate thread safety) is entirely absent — it just says 'read the reference.' | 2 / 3 |
Progressive Disclosure | It correctly points to a single reference file one level deep, which is good structure. However, the SKILL.md itself provides almost no usable quick-start content — it's essentially just a long bullet list and a pointer, offering no standalone value before the reader must navigate to the reference. | 2 / 3 |
Total | 7 / 12 Passed |
Validation
100%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 11 / 11 Passed
Validation for skill structure
No warnings or errors.
- Repository
- jabrena/cursor-rules-java
- Commit
9ec21dd
- Reviewed
Table of Contents
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