what is linked hashmap in java code example

Example 1: hashmap and linkedhashmap

Main difference between HashMap and LinkedHashMap
I remember is that LinkedHashMap maintains
insertion order of keys, 
On the other hand HashMap doesn't maintain
any order or keys or values.
Also LinkedHashMap requires more memory than HashMap
because of the ordering feature.
LinkedHashMap doublly Linked List to 
maintain order of elements.

Example 2: linked hashmap

LinkedHashMap can have null key, keeps order