Why should I override hashCode() when I override equals() method?

Question

Ok, I have heard from many places and sources that whenever I override the equals() method, I need to override the hashCode() method as well. But consider the following piec

Answer 1

It is primarily important when searching for an object using its hashCode() value in a collection (i.e. HashMap, HashSet, etc.). Each object returns a different hashCode() value therefore you must override this method to consistently generate a hashCode value based on the state of the object to help the Collections algorithm locate values on the hash table.