如何处理列表首选项的重复值？

const list = [1, 2, 3, 2, 4, 1];
const uniqueList = [...new Set(list)];
console.log(uniqueList); // 输出：[1, 2, 3, 4]

list = [1, 2, 3, 2, 4, 1]
uniqueList = list(dict.fromkeys(list))
print(uniqueList) # 输出：[1, 2, 3, 4]

import java.util.ArrayList;
import java.util.Collections;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        list.add(2);
        list.add(4);
        list.add(1);

        Collections.sort(list);
        list.removeIf((Integer current) -> {
            int index = list.indexOf(current);
            return index != -1 && index != list.lastIndexOf(current);
        });

        System.out.println(list); // 输出：[1, 2, 3, 4]
    }
}