Java Class 37 Map, Hash map, Linked hash map & Tree map, hash table (27/4/2023)

Map: map is an interface. Map is working on key and value. Map have multiple classes like – Hash map Linked hash map Tree map 1. Hash map: hash map is a class implements a Map interface. Hash map is working on key and value pair. Key and value we can say like entry. Hash map is contains only unique key but value can be store as duplicate. Hash map is not maintain insertion order. in Tree map: null key is not allow but null value can be allow. in hash table can't be allow null key and null value.