---
id: java-do-while-loop
title: "Java Do While Loop"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["do-while loop", "자바 do-while 반복문"]
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", "loops", "do-while"]
raw_sources: ["https://www.w3schools.com/java/java_while_loop_do.asp"]
applied_in: []
github_commit: ""
---

# [[Java Do While Loop]]

## 🎯 한 줄 통찰 (One-line insight)
The do/while loop's defining trait is executing the body BEFORE the first condition check — even with `int i = 10; do {...} while (i < 5);`, the false-from-the-start condition still lets the body run exactly once, the exact opposite of a plain while loop. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`do { ... } while (condition);`** — runs the block once, then repeats while the condition holds. [S1]
- **Required semicolon** — the `;` after `while (condition)` is mandatory. [S1]
- **Guaranteed first run** — unlike `while`, the body always executes at least once, regardless of the initial condition. [S1]
- **Use case** — anything that must happen at least once, e.g. showing a message or prompting for input. [S1]

## 📖 세부 내용 (Details)
- Basic do/while: `int i = 0; do { System.out.println(i); i++; } while (i < 5);`. [S1]
- False-from-start still runs once: `int i = 10; do { System.out.println("i is " + i); i++; } while (i < 5);` — prints once despite the condition being false immediately. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **while 루프와의 핵심 차이**: while은 조건이 처음부터 거짓이면 아예 실행되지 않지만, do/while은 최소 한 번은 실행된다는 점이 명시적으로 대비됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 사용자 입력 프롬프트, 메뉴 표시 등 "최소 1회 실행" 이 필요한 상황에 사용된다. [S1]

## 💻 코드 패턴 (Code patterns)
Do/while always runs once, even with a false-from-start condition (Java):
```java
int i = 10;
do {
    System.out.println("i is " + i);
    i++;
} while (i < 5);
```

## ✅ 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 While Loop]], [[Java For Loop]]
- **참조 맥락:** while 루프의 변형 — 최소 1회 실행 보장이 핵심 차이.

## 📚 출처 (Sources)
- [S1] W3Schools — Java Do/While Loop — https://www.w3schools.com/java/java_while_loop_do.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "Java Do/While Loop" page (Astra wiki-curation, P-Reinforce v3.1 format).