design-patterns SKILL.md skillA
design-patterns from decebals/claude-code-java is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add decebals/claude-code-java/design-patterns@git:20260828.702770aPins git:20260828.702770a in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- decebals/claude-code-java
- Path
skills/design-patterns/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260828.702770a, committed Aug 28, 2026
- Size
- 17,606 bytes
- Repository stars
- 759
- License
- MIT
Common design patterns with Java examples (Factory, Builder, Strategy, Observer, Decorator, etc.). Use when user asks "implement pattern", "use factory", "strategy pattern", or when designing extensible components.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Design Patterns Skill
Practical design patterns reference for Java with modern examples.
## When to Use
- User asks to implement a specific pattern
- Designing extensible/flexible components
- Refactoring rigid code structures
- Code review suggests pattern usage
---
## Quick Reference: When to Use What
| Problem | Pattern |
|---------|---------|
| Complex object construction | **Builder** |
| Create objects without specifying class | **Factory** |
| Multiple algorithms, swap at runtime | **Strategy** |
| Add behavior without changing class | **Decorator** |
| Notify multiple objects of changes | **Observer** |
| Ensure single instance | **Singleton** |
| Convert incompatible interfaces | **Adapter** |
| Define algorithm skeleton | **Template Method** |
---
## Creational Patterns
### Builder
**Use when:** Object has many parameters, some optional.
```java
// ❌ Telescoping constructor antipattern
public class User {
public User(String name) { }
public User(String name, String email) { }
public User(String name, String email, int age) { }
public User(String name, String email, int age, String phone) { }
// ... explosion of constructors
}
…Read the whole file at its exact version.
How to install
mdr add decebals/claude-code-java/design-patterns@sha256:416a60615b34770cThe line at the top of this page pins the label git:20260828.702770a, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_lfpe3b4c7o3sqbxc)
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Versions
The registry has recorded 1 version of this file, committed on Aug 28, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (17606 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
decebals/claude-code-java · 759 stars · license MIT · pushed 2026-09-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_lfpe3b4c7o3sqbxc GET https://markdownregistry.com/api/v1/resolve?ref=decebals/claude-code-java/design-patterns GET https://markdownregistry.com/api/v1/blob/416a60615b34770cf71ea2a890c9013502076c54a4cb760c6a5640b6bf36feb9
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