What would be the result if we overrode the equals method properly

Question

import java.util.*;
class Nearly{
   String value:
   Nearly(String v){ value = v;}
   public int hashCode(){ return 1;}
   public boolean equals(Nearly n){
   if(value.charAt(0) == n.value.charAt(0)) return true;
   return false;
   public static void mian(String [] sss){
     Nearly n1 = new Nearly("aaa");
     Nearly n2 = new Nearly("aaa");
     String s = "_";
     if(n1.equals(n2)) s += "1";
     if(n1==n2) s += "2";
     Set <Nearly> set = new HashSet <Nearly>();
      set.add(n1);
      set.add(n2);
     System.out.println(s + " " + set.size());
}Ans: b) -1 2
Reason: Two different equals() methods are invoked, because the equals() method shown in the code doesn't properly override Object.equals(), which takes an Object
Ok so what would have been the result if the equals() method was something like this:
public boolean equals(Object n)
{I guess my question is about the overriding the equals() method which i am not able to understand

Answer 1

pksingh79 wrote:
what would be the result if we overrode the equals method properlyThe result would be a method, the functionality of which would adhere to Object#equals()'s contract:
public boolean equals(Object obj)
Indicates whether some other object is "equal to" this one.
The equals method implements an equivalence relation on non-null object references:
&#42; It is reflexive: for any non-null reference value x, x.equals(x) should return true.
&#42; It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and
only if y.equals(x) returns true.
&#42; It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and
y.equals(z) returns true, then x.equals(z) should return true.
&#42; It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y)
consistently return true or consistently return false, provided no information used in equals
comparisons on the objects is modified.
&#42; For any non-null reference value x, x.equals(null) should return false.