Equals Method Overloading – Java Puzzlers Advent Calendar1日目 – Javaビーム研究所

Equals Method Overloading import java.util.*; class Student { private int id; Student(int id) { this.id = id; } public boolean equals(Student student) { return student != null && student.id == id; } @Override public int hashCode() { return Objects.hash(id); } } public class Main { public static void main(String[] args) { List<Student> students = new ArrayList<>(); students.add(new Student(1)); stu

[tyru]

Objects#hash() なんて便利メソッドがあったのか… まぁ lombok 使うけど