2nd/10_Wiki/Dev/Topic_Java/Java_Strings.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-strings	Java Strings	Programming_Language	draft	conceptual		자바 문자열		B	0.9	2026-07-04	2026-07-04			java programming w3schools strings	https://www.w3schools.com/java/java_strings.asp

Java Strings

🎯 한 줄 통찰 (One-line insight)

A Java String is an object with methods, not a raw character array — length(), indexOf(), charAt(), equals(), and trim() are all method calls (str.method()), not built-in functions like Python's len(str). [S1]

🧠 핵심 개념 (Core concepts)

• String — a double-quoted, object-based text container in Java (not a primitive). [S1]
• length() — returns character count. [S1]
• toUpperCase() / toLowerCase() — case conversion. [S1]
• indexOf(text) — position of the first occurrence (0-indexed). [S1]
• charAt(index) — the character at a specific position. [S1]
• equals(other) — compares string CONTENT, unlike == which compares references. [S1]
• trim() — removes leading/trailing whitespace. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Method-call syntax throughout — every string operation is str.method(), contrasting with Python's mix of methods (str.upper()) and built-in functions (len(str)). [S1]
• equals() not == — the tutorial specifically teaches equals() for string comparison, implying == would compare object references rather than content (a classic Java gotcha, though not elaborated here). [S1]

📖 세부 내용 (Details)

• Length: String txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; txt.length(). [S1]
• Case conversion: txt.toUpperCase(); txt.toLowerCase();. [S1]
• Find position: String txt = "Please locate where 'locate' occurs!"; txt.indexOf("locate"); // 7. [S1]
• Character access: String txt = "Hello"; txt.charAt(0); // H. [S1]
• Content comparison: txt1.equals(txt2). [S1]
• Trim whitespace: String txt = " Hello World "; txt.trim(); // "Hello World". [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 이후 Concatenation/Numbers and Strings/Special Characters 챕터에서 문자열 조작이 심화된다. [S1]

💻 코드 패턴 (Code patterns)

Content comparison with equals() (Java):

String txt1 = "Hello";
String txt2 = "Hello";
System.out.println(txt1.equals(txt2));  // true

✅ 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 Strings Concat, Java Strings Numbers, Java Characters
• 참조 맥락: 문자열 메서드의 기초 — equals()로 내용 비교(==와 구분)해야 함이 핵심.

📚 출처 (Sources)

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

📝 변경 이력 (Change history)

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