What's The Effect of Hashcode () & equals () when adding object to listsetmap

- SET & MAP A - Object / Key EXISTS IN SET / MAP B - Object / Key To Be Added To Set / Map if And Only IF (B == A || B.Equals (a)) && B.hashcode == a.hashcode the keyadd Will Overwrite The Existed One. - list can add anybject Can Add the Same Object More Than ONE TIME