---
id: java-treeset
title: "Java TreeSet"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["자바 TreeSet"]
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", "collections-framework", "treeset"]
raw_sources: ["https://www.w3schools.com/java/java_treeset.asp"]
applied_in: []
github_commit: ""
---

# [[Java TreeSet]]

## 🎯 한 줄 통찰 (One-line insight)
TreeSet's automatic sorting comes at a real performance cost — the comparison table explicitly rates HashSet "faster (no sorting)" against TreeSet "slower (due to sorting)", so the choice between them is a genuine speed-vs-order trade-off, not a free upgrade. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`TreeSet`** — stores unique elements in automatically sorted (natural) order. [S1]
- **Same API as HashSet** — `add()`, `contains()`, `remove()`, `clear()`, `size()`, for-each loop. [S1]
- **Works for numbers too** — sorts Integer elements from smallest to largest, not just Strings alphabetically. [S1]
- **Performance trade-off** — TreeSet is slower than HashSet due to maintaining sort order. [S1]

## 📖 세부 내용 (Details)
- String sort: `TreeSet<String> cars = new TreeSet<>(); cars.add("Volvo"); cars.add("BMW"); cars.add("Ford"); cars.add("Mazda"); // sorted: [BMW, Ford, Mazda, Volvo]`. [S1]
- Integer sort: `TreeSet<Integer> numbers = new TreeSet<>(); numbers.add(40); numbers.add(10); numbers.add(30); numbers.add(20); // iterates 10, 20, 30, 40`. [S1]
- Comparison table: HashSet (no order, faster) vs. TreeSet (sorted natural order, slower). [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 정렬된 순서가 필요한 유일값 집합(랭킹, 알파벳순 목록 등)에 TreeSet이 쓰인다. [S1]

## 💻 코드 패턴 (Code patterns)
TreeSet automatically sorts numbers on insertion (Java):
```java
TreeSet<Integer> numbers = new TreeSet<>();
numbers.add(40);
numbers.add(10);
numbers.add(30);
numbers.add(20);
for (int n : numbers) {
    System.out.println(n); // 10, 20, 30, 40
}
```

## ✅ 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 HashSet]], [[Java LinkedHashSet]], [[Java Set]]
- **참조 맥락:** 정렬이 필요한 Set 구현체 — LinkedHashSet(삽입 순서 보존) 챕터로 이어짐.

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

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