# iluwatar/java-design-patterns

Design patterns implemented in Java

Repository: https://github.com/iluwatar/java-design-patterns
Canonical: https://ross.abutalabs.com/products/java-design-patterns
Homepage: https://java-design-patterns.com
Language: Java
License: NOASSERTION
License Family: other
Topics: java, principles, design-patterns, awesome-list, snippets, snippets-collection, snippets-library, hacktoberfest
Last push: 2026-08-25T04:52:07+00:00

## Health v2 (maintenance only)
Score: 77/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 35, longevity 100
- inputs: {"age_days": 4407, "days_push": 8, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 94625, forks 27395 (observed 2026-08-28T04:12:23.520453+00:00)

## What it is
A large open-source collection of classic and modern software design patterns implemented in Java, with well-commented source code examples, software design principles, and reusable Java 17 code snippets. It serves as a browsable tutorial catalog for learning object-oriented design practices.

## Use cases
- learn how to implement the singleton pattern in java
- find a java example of the observer pattern
- study software design principles before an interview
- browse copy-pasteable java code snippets
- understand the difference between factory and abstract factory patterns
- teach design patterns in a software engineering course

## When to choose
- you want well-commented, runnable Java examples of design patterns
- you are learning or teaching object-oriented design
- you need reference implementations to guide refactoring toward idiomatic patterns

## When to avoid
- you need a production library to import rather than educational example code
- you work in a language other than Java
- you need a formal design-pattern certification or textbook-only material

## Facets
- artifact type: learning-resource
- maturity: active
- function: developer-tools, documentation
- domain: developer-tools, tutorials, programming-languages
- platform: jvm
- tags: design-patterns, java, code-snippets, educational, object-oriented-design

## Member repositories
- iluwatar/java-design-patterns (main) score 77

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:12:23.520453+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T16:12:43.649949+00:00, confidence not recorded.
  - readme: https://github.com/iluwatar/java-design-patterns (fetched 2026-08-28T04:12:23.520453+00:00, sha 17407e883407)
  - homepage: https://java-design-patterns.com (fetched 2026-08-28T17:35:23.239016+00:00, sha 19e3626e6612)
- Data as of 2026-08-30T08:39:29.467469+00:00.