142-java-functional-programming
Use when you need to apply functional programming principles in Java — including writing immutable objects and Records, pure functions, functional interfaces, lambda expressions, Stream API pipelines, Optional for null safety, function composition, higher-order functions, pattern matching for instanceof and switch, sealed classes/interfaces for controlled hierarchies, Stream Gatherers for custom operations, currying/partial application, effect boundary separation, and concurrent-safe functional patterns. Part of the skills-for-java project
77
71%
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/142-java-functional-programming/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 comprehensively lists specific functional programming capabilities in Java with excellent trigger term coverage. It includes an explicit 'Use when...' clause and is highly distinctive due to its focus on Java-specific functional programming concepts. The description is thorough without being padded with fluff, using third person voice appropriately.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'writing immutable objects and Records, pure functions, functional interfaces, lambda expressions, Stream API pipelines, Optional for null safety, function composition, higher-order functions, pattern matching, sealed classes/interfaces, Stream Gatherers, currying/partial application, effect boundary separation, concurrent-safe functional patterns.' | 3 / 3 |
Completeness | Explicitly answers both what (comprehensive list of functional programming concepts and techniques) AND when ('Use when you need to apply functional programming principles in Java'). The 'Use when...' clause is present and clear. | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms users would say: 'functional programming', 'Java', 'immutable objects', 'Records', 'lambda expressions', 'Stream API', 'Optional', 'pattern matching', 'sealed classes', 'currying'. These are terms developers naturally use when seeking functional programming guidance. | 3 / 3 |
Distinctiveness Conflict Risk | Clear niche targeting specifically 'functional programming principles in Java' with distinct triggers like 'Records', 'Stream API', 'Optional', 'sealed classes'. Unlikely to conflict with general Java skills or functional programming in other languages due to Java-specific terminology. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
42%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill has good structure and appropriate progressive disclosure to a reference file, but the main body lacks actionable content. It reads more like a table of contents than operational guidance - listing concepts without providing concrete examples or clear application workflows. The safety constraints around compilation are well-specified, but the core functional programming guidance is entirely deferred.
Suggestions
Add 2-3 concrete before/after code examples directly in the skill body showing common transformations (e.g., imperative loop → Stream pipeline, null checks → Optional chain)
Include a brief decision workflow: 'When you see X pattern, apply Y transformation' with specific triggers
Remove the concept inventory bullets (Claude knows what Records and Streams are) and replace with actionable transformation rules
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill lists many concepts Claude already knows (what Records are, what Stream API is, etc.) without adding novel guidance. The bullet-point inventory is somewhat redundant given the reference file exists, though it's not excessively verbose. | 2 / 3 |
Actionability | No concrete code examples, commands beyond compile/verify, or executable guidance in the skill body itself. It describes what topics are covered but doesn't show how to apply them - all actual guidance is deferred to the reference file. | 1 / 3 |
Workflow Clarity | The constraints section provides a clear compile-first workflow with validation steps, but the actual functional programming application process is vague ('Apply recommendations based on applicable examples'). Missing explicit steps for how to identify and apply patterns. | 2 / 3 |
Progressive Disclosure | Clean structure with overview, constraints, usage triggers, and a single well-signaled reference file. Appropriately delegates detailed examples to the reference document without deep nesting. | 3 / 3 |
Total | 8 / 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
7772a1b
- Reviewed
Table of Contents
Is this your skill?
If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.