---
id: java-polymorphism
title: "Java Polymorphism"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["자바 다형성"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.9
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["java", "programming", "w3schools", "oop", "polymorphism"]
raw_sources: ["https://www.w3schools.com/java/java_polymorphism.asp"]
applied_in: []
github_commit: ""
---

# [[Java Polymorphism]]

## 🎯 한 줄 통찰 (One-line insight)
Declaring `Animal myPig = new Pig();` — parent type on the left, subclass instance on the right — is the exact mechanism that lets `myPig.animalSound()` call Pig's overridden version, not Animal's default: polymorphism means the SAME method call resolves differently depending on the actual object type, not the declared variable type. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Polymorphism** — "many forms"; occurs when related classes (via inheritance) implement the same method differently. [S1]
- **Method overriding across subclasses** — each subclass (Pig, Dog) provides its own `animalSound()` implementation. [S1]
- **Same action, different behavior** — calling `animalSound()` on different object types produces different output through one shared method name. [S1]
- **Parent-typed reference to subclass instance** — `Animal myPig = new Pig();` is valid and dispatches to Pig's override. [S1]

## 📖 세부 내용 (Details)
- Overridden methods: `class Animal { public void animalSound() { System.out.println("The animal makes a sound"); } } class Pig extends Animal { public void animalSound() { System.out.println("The pig says: wee wee"); } } class Dog extends Animal { public void animalSound() { System.out.println("The dog says: bow wow"); } }`. [S1]
- Polymorphic dispatch: `Animal myAnimal = new Animal(); Animal myPig = new Pig(); Animal myDog = new Dog(); myAnimal.animalSound(); myPig.animalSound(); myDog.animalSound();` — each call produces the subclass-specific sound. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — Animal/Pig/Dog 계층은 다형성 개념의 표준 교육용 예제다. [S1]

## 💻 코드 패턴 (Code patterns)
Polymorphic method dispatch via parent-typed references (Java):
```java
Animal myAnimal = new Animal();
Animal myPig = new Pig();
Animal myDog = new Dog();
myAnimal.animalSound(); // The animal makes a sound
myPig.animalSound();    // The pig says: wee wee
myDog.animalSound();    // The dog says: bow wow
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.90
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[Java Tutorial]]
- **관련 개념:** [[Java Inheritance]], [[Java Super Keyword]], [[Java Abstraction]], [[Java Interface]]
- **참조 맥락:** 상속 기반 메서드 오버라이딩의 활용 — super 키워드 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — Java Polymorphism — https://www.w3schools.com/java/java_polymorphism.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "Java Polymorphism" page (Astra wiki-curation, P-Reinforce v3.1 format).