I know this will probably be a ohhhhhhhh moment when someone explains this to me. What are some reasons or real world situations you might want to use a HashSet? From my understanding you need a Class that is considered .equal() to the class your looking for. So even though this is user defined if the class you have is pretty much equal to the class your trying to get in the HashSet then where is the need?
side note I read that HashMaps can't have duplicates. Does this apply to the hash key or the Objects that are being held?
Im new to most of the Collections so if there is anything wrong within my question showing that my understanding of either Hash Type is screwed up then please let me know.