How is the implementation of LinkedHashMap different from HashMap?

Question

If LinkedHashMap\'s time complexity is same as HashMap\'s complexity why do we need HashMap? What are all the extra overhead LinkedHashMap has when compared to HashMap in Ja

Answer 1

LinkedHashMap will take more memory. Each entry in a normal HashMap just has the key and the value. Each LinkedHashMap entry has those references and references to the next and previous entries. There's also a little bit more housekeeping to do, although that's usually irrelevant.