2nd/10_Wiki/Topics/Topic_Programming/Topic_Java/Java_Interface.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
java-interface	Java Interface	Programming_Language	draft	conceptual		implements keyword 자바 인터페이스		B	0.9	2026-07-04	2026-07-04			java programming w3schools oop interface	https://www.w3schools.com/java/java_interface.asp

Java Interface

🎯 한 줄 통찰 (One-line insight)

Interfaces exist specifically to work around Java's single-inheritance limitation — a class can only extends one superclass, but it can implements multiple interfaces (comma-separated), making interfaces Java's mechanism for something resembling multiple inheritance. [S1]

🧠 핵심 개념 (Core concepts)

• Interface — a fully "abstract class" grouping related methods that all lack bodies. [S1]
• implements — the keyword a class uses to adopt an interface (vs. extends for classes). [S1]
• Mandatory override — implementing a class MUST override every method the interface declares. [S1]
• Implicit modifiers — interface methods are abstract + public by default; interface attributes are public, static, final by default. [S1]
• No constructor — interfaces cannot have constructors (can't be instantiated). [S1]
• Multiple interfaces — a class can implement several interfaces, separated by commas — Java's substitute for multiple inheritance. [S1]

📖 세부 내용 (Details)

• Interface declaration: interface Animal { public void animalSound(); public void run(); }. [S1]
• Implementation: class Pig implements Animal { public void animalSound() { System.out.println("The pig says: wee wee"); } public void sleep() { System.out.println("Zzz"); } }. [S1]
• Multiple interfaces: class DemoClass implements FirstInterface, SecondInterface { public void myMethod() {...} public void myOtherMethod() {...} }. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 다중 상속 대안: Java는 클래스의 다중 상속을 지원하지 않지만, 인터페이스 다중 구현으로 유사 효과를 달성한다는 점이 명시됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 여러 인터페이스를 한 클래스가 동시에 구현하는 패턴이 다중 상속의 대체 수단으로 쓰인다. [S1]

💻 코드 패턴 (Code patterns)

Class implementing multiple interfaces (Java):

interface FirstInterface {
    public void myMethod();
}
interface SecondInterface {
    public void myOtherMethod();
}
class DemoClass implements FirstInterface, SecondInterface {
    public void myMethod() {
        System.out.println("Some text..");
    }
    public void myOtherMethod() {
        System.out.println("Some other text...");
    }
}

✅ 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 Abstraction, Java Anonymous, Java Enums
• 참조 맥락: 다중 상속의 대안 — 익명 클래스 챕터에서 인터페이스를 즉석 구현하는 방법으로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — Java Interface — https://www.w3schools.com/java/java_interface.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "Java Interface" page (Astra wiki-curation, P-Reinforce v3.1 format).