java HashSet

public class HashSetDemo {
    public static void main(String[] args) {
        HashSet hs = new HashSet();
        hs.add(new Person("a1",1));
        hs.add(new Person("a2",2));
        hs.add(new Person("a3",3));
        hs.add(new Person("a2",2));
        Iterator it = hs.iterator();
        while (it.hasNext()){
            Person p = (Person) it.next();
            System.out.println(p.getName()+"**"+p.getAge());
        }
    }
}

class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Person))
            return false;
        Person p = (Person) obj;
        return this.getName().equals(p.name) && this.getAge() == p.age;
    }

    @Override
    public int hashCode() {
        return name.hashCode()+age*39;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}