It doesn't; it's just that you probably never heard the quack of a hashmap so you don't know the difference.
A hashmap is a very specific structure that uses a hashing algorithm to normalize the key sizes, and then usually constructs a tree-like structure for fast key lookups. Anything that doesn't use such an implementation under the hood should not be called a hashmap, whether you care or not.
A hashmap is a very specific structure that uses a hashing algorithm to normalize the key sizes, and then usually constructs a tree-like structure for fast key lookups. Anything that doesn't use such an implementation under the hood should not be called a hashmap, whether you care or not.