2nd/10_Wiki/Dev/Topic_Java/Java_Date.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-date	Java Date	Programming_Language	draft	conceptual		java.time package 자바 날짜와 시간		B	0.9	2026-07-04	2026-07-04			java programming w3schools date time java.time	https://www.w3schools.com/java/java_date.asp

Java Date

🎯 한 줄 통찰 (One-line insight)

Java has NO built-in Date class of its own — dates/times require importing the java.time package (LocalDate/LocalTime/LocalDateTime/DateTimeFormatter), a design choice the tutorial states upfront rather than assuming a language-level date type. [S1]

🧠 핵심 개념 (Core concepts)

• java.time package — required import for all date/time functionality. [S1]
• LocalDate — represents a date only (yyyy-MM-dd). [S1]
• LocalTime — represents a time only (HH-mm-ss-ns). [S1]
• LocalDateTime — combines both date and time. [S1]
• DateTimeFormatter — formats/parses date-time objects via ofPattern(...). [S1]
• .now() — static method on LocalDate/LocalTime/LocalDateTime returning the current value. [S1]
• The "T" separator — LocalDateTime's default string form uses "T" to separate date from time; removable via formatting. [S1]

📖 세부 내용 (Details)

• Current date: LocalDate myObj = LocalDate.now(); // 2026-07-04. [S1]
• Current time: LocalTime myObj = LocalTime.now(); // 9:58:29.366162. [S1]
• Current date+time: LocalDateTime myObj = LocalDateTime.now(); // 2026-07-04T09:58:29.366392. [S1]
• Custom formatting: DateTimeFormatter myFormatObj = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm:ss"); String formattedDate = myDateObj.format(myFormatObj); // 04-07-2026 09:58:29. [S1]
• Pattern examples: yyyy-MM-dd → "1988-09-29"; dd/MM/yyyy → "29/09/1988"; dd-MMM-yyyy → "29-Sep-1988"; E, MMM dd yyyy → "Thu, Sep 29 1988". [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 로그 타임스탬프, 사용자 표시용 날짜 포맷 변환의 표준 패턴이다. [S1]

💻 코드 패턴 (Code patterns)

Custom date-time formatting (Java):

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

LocalDateTime myDateObj = LocalDateTime.now();
DateTimeFormatter myFormatObj = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm:ss");
String formattedDate = myDateObj.format(myFormatObj);

✅ 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 Packages, Java User Input, Java Errors
• 참조 맥락: java.time 패키지를 통한 날짜/시간 처리 — 에러/예외 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — Java Date and Time — https://www.w3schools.com/java/java_date.asp

📝 변경 이력 (Change history)

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