docs(10_Wiki): Dev 폴더 누락분 반영 — Topic_Programming으로 통합

이전 재구성 작업에서 Dev/ 폴더가 누락되었던 것을 반영. - Dev/Topic_Programming(중첩 폴더, 78개)은 Dev 자체 최상위 폴더들 (Architecture/Conventions/Engineering_Intelligence 등)과 완전 중복이라 제거. - Dev 최상위 엔지니어링 지식 폴더(Architecture/Conventions/Engineering_Intelligence/ Failure_Library/Generalized_Principles/Language/Pattern_Catalog/Platform_Guides/ Subsystems, 77개)는 이미 Topic_Programming/Topic_Programming에 더 최신 버전이 존재해 중복 제거(고유 콘텐츠 1개는 예외 처리하여 이동 보존). - Dev의 W3Schools 언어 튜토리얼 폴더(Topic_C/CPP/CSS/CSharp/HOWTO/HTML/Java/ JavaScript/PHP/Python/SQL/W3CSS, 1201개)는 전부 Topic_Programming 하위로 이동. - 에이전트 운영 상태(.astra/docs)는 그대로 유지, 콘텐츠 폴더만 정리. - Topic_Programming 최종 문서 수: 2784 → 3985.
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+---
+id: java-if-else
+title: "Java If Else"
+category: "Programming_Language"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["if statement", "자바 조건문"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["java", "programming", "w3schools", "conditions", "if"]
+raw_sources: ["https://www.w3schools.com/java/java_conditions.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[Java If Else]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+Omitting curly braces after `if` is legal Java but dangerous — only the single next line belongs to the condition, so any subsequent line silently runs unconditionally, which is why the source explicitly recommends always using braces even for one-line bodies. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **`if (condition) { ... }`** — executes a block only when the condition evaluates to true. [S1]
+- **Condition must be boolean** — either a boolean expression (`x > y`) or a boolean variable (`isLightOn`). [S1]
+- **Case sensitivity** — `if` must be lowercase; `If`/`IF` causes a compile error. [S1]
+- **Boolean variable shorthand** — `if (isLightOn)` is equivalent to `if (isLightOn == true)` but shorter. [S1]
+- **Braceless if** — a single-statement body can omit `{ }`, but only the immediately following line is conditional. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Braceless-if trap** — `if (x > y) System.out.println("a"); System.out.println("b");` runs `println("b")` unconditionally even though it looks indented under the if — the source calls this a "Potential Problem" and recommends ALWAYS using braces to prevent subtle bugs. [S1]
+
+## 📖 세부 내용 (Details)
+- Basic condition: `if (20 > 18) { System.out.println("20 is greater than 18"); }`. [S1]
+- Variable comparison: `int x = 20; int y = 18; if (x > y) { System.out.println("x is greater than y"); }`. [S1]
+- Equality check: `if (x == y) { System.out.println("x is equal to y"); }`. [S1]
+- Boolean variable directly: `boolean isLightOn = true; if (isLightOn) { System.out.println("The light is on."); }`. [S1]
+- Braceless (risky): `if (20 > 18) System.out.println("20 is greater than 18");`. [S1]
+- Safe pattern: always wrap in `{ }`, even multi-statement blocks. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+- **소스가 직접 경고하는 함정**: 중괄호 생략 시 첫 줄만 조건에 속하고 이후 줄은 무조건 실행된다는 점. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — else/else if/switch로 이어지는 조건문 체계의 출발점이다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Safe if with braces (Java):
+```java
+int x = 20;
+int y = 18;
+if (x > y) {
+    System.out.println("x is greater than y");
+    System.out.println("Both lines are part of the if");
+}
+System.out.println("I am outside if, not part of if!");
+```
+
+## ✅ 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 Booleans]], [[Java Else]], [[Java Else If]], [[Java Switch]]
+- **참조 맥락:** 조건문 체계의 시작점 — else, else if, switch로 이어진다.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — Java If ... Else — https://www.w3schools.com/java/java_conditions.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "Java Conditions and If Statements" page (Astra wiki-curation, P-Reinforce v3.1 format).