面试官：了解HashSet吗？请做下面的题目

import java.util.HashSet;
 
public class Main {
    public static void main(String[] args) {
        HashSet set = new HashSet();
        Person p1 = new Person(1001, "AA");
        Person p2 = new Person(1002, "BB");
        set.add(p1);
        set.add(p2);
        System.out.println(set);	//(1001, AA), (1002, BB)
	
        p1.setName("CC"); 
        set.remove(p1);
        System.out.println(set); // (1002,BB),(1001,CC)
	
        set.add(new Person(1001, "CC")); 
        System.out.println(set); // (1002,BB),(1001,CC),(1001,CC)
 
        set.add(new Person(1001, "AA"));
        System.out.println(set); //(1002,BB),(1001,CC),(1001,CC),(1001,AA)
    }
}
 
class Person {
    private int id;
    private String name;
 
    public Person(int id, String name) {
        this.id = id;
        this.name = name;
    }
 
    public void setId(int id) {
        this.id = id;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Person)) return false;
 
        Person person = (Person) o;
 
        if (id != person.id) return false;
        return name != null ? name.equals(person.name) : person.name == null;
 
    }
 
    @Override
    public int hashCode() {
        int result = id;
        result = 31 * result + (name != null ? name.hashCode() : 0);
        return result;
    }
 
    @Override
    public String toString() {
        return "Person{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}