HashSets
A simple representation of how equals and hashcode methods work. In this project I also use Set interface which extends Collection. With the use of HashSet class which implements Set interface, I am showing that duplicate objects cannot be stored into the Collection.
The hashCode contract (Use JavaDoc for in-depth explanation) Objects that are equal must have the same hash code within a running process. Whenever you implement equals, you MUST also implement hashCode! Common faults:
Unequal objects must have different hash codes – WRONG
Objects with the same hash code must be equal – WRONG