2nd/10_Wiki/Topics/Topic_Programming/Topic_Java/Java_Variables.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-variables	Java Variables	Programming_Language	draft	conceptual		자바 변수		B	0.9	2026-07-04	2026-07-04			java programming w3schools variables	https://www.w3schools.com/java/java_variables.asp

Java Variables

🎯 한 줄 통찰 (One-line insight)

Unlike Python, Java is statically typed — every variable declaration must state a type (type variableName = value;), and that type cannot silently change later the way Python's dynamic typing allows. [S1]

🧠 핵심 개념 (Core concepts)

• Basic types — String (text, double-quoted), int (whole numbers), float (decimals), char (single character, single-quoted), boolean (true/false). [S1]
• Declaration syntax — type variableName = value;. [S1]
• Declare-then-assign — int myNum; myNum = 15; is also valid, splitting declaration and assignment. [S1]
• Reassignment overwrites — assigning a new value replaces the old one. [S1]
• final keyword — makes a variable unchangeable/read-only; reassigning raises a compile error. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Static typing is the core Java/Python divergence — every Java variable's type is fixed at declaration and enforced by the compiler, unlike Python where x = 4; x = "Sally" is legal. [S1]

📖 세부 내용 (Details)

• String declaration: String name = "John"; System.out.println(name);. [S1]
• Int declaration: int myNum = 15;. [S1]
• Separate declare/assign: int myNum; myNum = 15;. [S1]
• Reassignment: int myNum = 15; myNum = 20;. [S1]
• final (immutable): final int myNum = 15; myNum = 20; // error. [S1]
• All basic types together: int myNum = 5; float myFloatNum = 5.99f; char myLetter = 'D'; boolean myBool = true; String myText = "Hello";. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 이후 Data Types 챕터에서 각 타입이 상세히 다뤄진다. [S1]

💻 코드 패턴 (Code patterns)

Five basic types declared (Java):

int myNum = 5;
float myFloatNum = 5.99f;
char myLetter = 'D';
boolean myBool = true;
String myText = "Hello";

✅ 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 Data Types, Java Constants Final, Python Variables
• 참조 맥락: 정적 타이핑이라는 Java의 핵심 특성 — Python의 동적 타이핑과 대비.

📚 출처 (Sources)

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

📝 변경 이력 (Change history)

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