import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

class Main {
    public static void main(String[] args) throws Exception {
        int arr[] = new int[]{1,2,3};
        List<Integer> list = new ArrayList<>(Arrays.asList(1,2,3,4,5));
        String str = "Hi";

        System.out.println(arr.length);         //Arrays        length      출력  3
        System.out.println(list.size());        //Collection    size()      출력  5
        System.out.println(str.length());       //String        length()    출력  2
    }
}