---
id: java-annotations
title: "Java Annotations"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["@Override", "@Deprecated", "자바 어노테이션"]
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", "annotations"]
raw_sources: ["https://www.w3schools.com/java/java_annotations.asp"]
applied_in: []
github_commit: ""
---

# [[Java Annotations]]

## 🎯 한 줄 통찰 (One-line insight)
`@Override` converts a silent bug into a compile error — without it, a typo like `makesound()` instead of `makeSound()` just creates an unrelated new method that never overrides anything (program still runs, just wrong), but WITH `@Override`, the same typo becomes a hard compiler error immediately, since the annotation asserts "this must match a superclass method." [S1]

## 🧠 핵심 개념 (Core concepts)
- **Annotation** — starts with `@`; gives extra information to the compiler/tools without changing runtime behavior. [S1]
- **`@Override`** — asserts a method overrides a superclass method; not required, but catches typo-based bugs at compile time. [S1]
- **`@Deprecated`** — marks a method/class as outdated; using it still works but triggers an IDE/compiler warning. [S1]
- **`@SuppressWarnings("unchecked")`** — tells the compiler to ignore a specific warning category (e.g. raw-type usage), useful for legacy code. [S1]

## 📖 세부 내용 (Details)
- @Override catching a typo: `class Dog extends Animal { @Override void makesound() { ... } } // error: method does not override or implement a method from a supertype`. [S1]
- @Deprecated: `@Deprecated static void oldMethod() { System.out.println("This method is outdated."); } // triggers deprecation warning when called`. [S1]
- @SuppressWarnings: `@SuppressWarnings("unchecked") public static void main(String[] args) { ArrayList cars = new ArrayList(); cars.add("Volvo"); }` — better fixed via `ArrayList<String> cars = new ArrayList<>();` instead of suppressing. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **@Override 생략 시 위험**: @Override를 제거해도 컴파일러가 경고하지 않으며, 프로그램이 실행은 되지만 의도한 오버라이드가 발생하지 않아 예기치 않게 동작할 수 있음이 명시됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — raw ArrayList 사용 시 발생하는 unchecked 경고를 억제하기보다 제네릭 타입을 명시해 근본적으로 고치는 방법이 권장된다. [S1]

## 💻 코드 패턴 (Code patterns)
@Override catching a method-name typo at compile time (Java):
```java
class Animal {
    void makeSound() { System.out.println("Animal sound"); }
}
class Dog extends Animal {
    @Override
    void makesound() { // typo — triggers compile error due to @Override
        System.out.println("Woof!");
    }
}
```

## ✅ 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 Polymorphism]], [[Java Generics]], [[Java RegEx]]
- **참조 맥락:** 컴파일러에 추가 정보를 제공하는 도구 — 정규표현식(RegEx) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — Java Annotations — https://www.w3schools.com/java/java_annotations.asp

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