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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)

📚 출처 (Sources)

📝 변경 이력 (Change history)

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