What does EnumSet really mean?

Question

I have the following example:

import java.util.EnumSet;
import java.util.Iterator;

public class SizeSet {

    public static void main(String[] args) {
             


        

Answer 1

According to Oracle doc

Enum sets are represented internally as bit vectors. This representation is extremely compact and efficient.

Readable, type safe, low memory footprint... What do you want more?