Все я сдаюсь, как только не пробовал ничего не пропускает
package com.javarush.task.task21.task2104;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
/*
Equals and HashCode
*/
public class Solution {
private final String first, last;
public Solution(String first, String last) {
this.first = first;
this.last = last;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || !(o instanceof Solution)) return false;
Solution solution = (Solution) o;
return (first != null && first==solution.first)&& (last != null && last==solution.last);
}
public int hashCode() {
return Objects.hash(first,last);
}
public static void main(String[] args) {
Set<Solution> s = new HashSet<>();
s.add(new Solution("Donald", "Duck"));
System.out.println(s.contains(new Solution("Donald", "Duck")));
}
}