Solid java

Skill fusengine/agents/plugins/solid/skills/solid-java

Use when writing or refactoring Java code, structuring modules/[feature]/ layers, or defining interfaces/ contracts (SOLID, files < 100 lines).From its SKILL.md

Install

npx -y skills add fusengine/agents --skill solid-java

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

22 stars22 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

SKILL.md

4.5 KB, 950 tokens by cl100k_base, as published. Nobody here has run it

<objective> SOLID Java enforces a modular architecture for Java 21+: every feature lives under `modules/[feature]/` (controllers, services, repositories, interfaces, models/DTOs) with shared code in `modules/core/`, interfaces live only in `modules/[feature]/interfaces/`, controllers stay under 50 lines and delegate to services, records are used for DTOs and sealed types for restricted hierarchies, and every public method carries Javadoc.

Before writing any new code it requires a DRY check against modules/core/services and modules/core/interfaces. See solid-principles.md for the overview, the per-principle references for SRP/OCP/LSP/ISP/DIP detail, and the templates for module/service/interface/repository/error/test scaffolding. </objective>

SOLID Java - Modular Architecture

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

fuse-ai-pilot:explore-codebase - Analyze existing architecture
fuse-ai-pilot:research-expert - Verify Java docs via Context7
fuse-ai-pilot:sniper - Post-implementation validation

DRY - Reuse Before Creating (MANDATORY)

Before writing ANY new code:

Grep the codebase for similar interfaces, services, or logic
Check shared locations: modules/core/services/, modules/core/interfaces/
If similar code exists -> extend/reuse instead of duplicate
If code will be used by 2+ features -> create it in modules/core/

Architecture (Modules MANDATORY)

Layer	Location	Max Lines
Controllers	`modules/[feature]/controllers/`	50
Services	`modules/[feature]/services/`	100
Repositories	`modules/[feature]/repositories/`	100
Interfaces	`modules/[feature]/interfaces/`	30
Models/DTOs	`modules/[feature]/models/`	50
Shared	`modules/core/{services,interfaces,models}/`	-

NEVER use flat src/ structure - always modules/[feature]/

Critical Rules (MANDATORY)

Rule	Value
File limit	100 lines (split at 90)
Controllers	< 50 lines, delegate to services
Interfaces	`modules/[feature]/interfaces/` ONLY
Javadoc	Every public method documented
Records	Use for DTOs (Java 16+)
Sealed	Use for restricted hierarchies (Java 17+)

Reference Guide

Concepts

Topic	Reference	When to consult
SOLID Overview	solid-principles.md	Quick reference
SRP	single-responsibility.md	Fat classes
OCP	open-closed.md	Adding providers
LSP	liskov-substitution.md	Contracts
ISP	interface-segregation.md	Fat interfaces
DIP	dependency-inversion.md	Injection
Architecture	architecture-patterns.md	Modular patterns

Templates

Template	When to use
module.md	Feature module structure
service.md	Business logic service
interface.md	Contract definition
repository.md	Data access layer
error.md	Custom exceptions
test.md	Unit tests with mocks

Forbidden

Anti-Pattern	Fix
Files > 100 lines	Split at 90
Interfaces in impl files	Move to `interfaces/` directory
`new ConcreteClass()` in services	Use dependency injection
Flat `src/` structure	Use `modules/[feature]/`
God classes	Split by responsibility

What ships with it: 13 files

45.8 KB alongside SKILL.md