There are three main types of Map in Java: HashMap, TreeMap, and LinkedHashMap.

• HashMap

A HashMap is an unordered map. This means that the order in which the keys and values are stored is not guaranteed. HashMaps are typically used when the order of the keys and values is not important.

• TreeMap

A TreeMap is an ordered map. This means that the keys and values are stored in sorted order. TreeMaps are typically used when the order of the keys and values is important.

• LinkedHashMap

A LinkedHashMap is a hybrid map. This means that it combines the features of a HashMap and a TreeMap. LinkedHashMaps are typically used when the order of the keys and values is important, but it is also important to be able to iterate over the keys and values in the order in which they were inserted.