HashCode.java

import java.util.HashSet;

import java.util.Objects;

 

class Person{

private String name;

private int age;

public Person(String name, int age) {

this.name = name;

this.age = age;

}

public String toString(){

return name + "(" + age + "세)";

}

 

@Override

public int hashCode(){

return Objects.hash(name, age);

}

 

@Override

public boolean equals(Object obj){

Person p = (Person)obj;

 

if(p.name.equals(name) && p.age == age)

return true;

else

return false;

}

}

 

public class HashCode{

public static void main(String[] args){

HashSet<Person> set = new HashSet<>();

 

set.add(new Person("Ham", 28));
set.add(new Person("Kim", 33));
set.add(new Person("Kang", 49));
set.add(new Person("Ham", 28));

System.out.println("인스턴스 수 : " + set.size());

 

for(Person p : set)

System.out.println(p.toString() + '\t');

}

}