HashSet

import java.util.HashSet;

 

//선언

HashSet<Integer> arr = new HashSet<>();

 

//추가

arr.add(0);

arr.add(1);

 

//삭제

arr.remove(0); //0 값 삭제

arr.clear(); //모두 삭제

 

//검색

arr.contains(0); //false

 

//크기

arr.size();

 

//출력

System.out.println(arr); //전체

Iterator itr = arr.Iterator();

while(itr.hasNext()) {

    System.out.print(iter.next() + " " );

}

 

//정렬

ArrayList<Integer> arrList = new ArrayList<>(arr);

Collections.sort(arrList);