2nd/10_Wiki/Topics/Domain_Programming/Topic_Java/Java_Scope.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-scope	Java Scope	Programming_Language	draft	conceptual		자바 변수 범위		B	0.9	2026-07-04	2026-07-04			java programming w3schools scope	https://www.w3schools.com/java/java_scope.asp

Java Scope

🎯 한 줄 통찰 (One-line insight)

A loop's counter variable dies when the loop ends, which means the same name (i, j) can be safely reused across separate loops in the same method — scope isn't just a restriction, it's what enables variable-name reuse without conflict. [S1]

🧠 핵심 개념 (Core concepts)

• Scope — the region where a variable is accessible; Java variables live only inside the region where they're created. [S1]
• Method scope — a variable is usable anywhere in the method AFTER its declaration line, not before. [S1]
• Block scope — { } delimits a block; a variable declared inside is accessible only within that block, and only after its declaration line. [S1]
• Loop scope — a variable declared in a for-loop header exists only inside that loop; it's destroyed once the loop ends. [S1]
• Name reuse across loops — since each loop's i is destroyed at loop end, separate loops in the same method can reuse the same variable name. [S1]

📖 세부 내용 (Details)

• Method scope: int x = 100; declared mid-method is unusable before its declaration line, usable after. [S1]
• Block scope: a variable declared inside { } is inaccessible both before the block and after it ends. [S1]
• Loop scope: for (int i = 0; i < 5; i++) { System.out.println(i); } // i is NOT accessible here. [S1]
• Reused loop variable names: two separate for (int i = 0; ...) loops in the same method, each with their own independent i. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 여러 반복문에서 동일한 변수명(i, j)을 안전하게 재사용할 수 있는 근거가 스코프 규칙이다. [S1]

💻 코드 패턴 (Code patterns)

Safe reuse of loop variable name across separate loops (Java):

for (int i = 0; i < 3; i++) {
    System.out.println("Loop 1: " + i);
}
for (int i = 0; i < 2; i++) {
    System.out.println("Loop 2: " + i);
}

✅ 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 For Loop, Java Methods, Java Recursion
• 참조 맥락: 변수 접근 범위 규칙 — 메서드/블록/반복문 스코프의 차이.

📚 출처 (Sources)

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

📝 변경 이력 (Change history)

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