Comparing three implementations of Set interface

Comparing three implementations of Set interface 

Classes implementing Set	Underlying data structure	Pros	Cons
HashSet	hash-table	1.        Useful when you want to impose only uniqueness among elements. 2.        Faster than other Set implementation as it does not need to maintain any order.	1.        Do not guarantee any order among elements. 2.        Not thread –safe.*
LinkedHashSet	hash-table and doubly linked list	1.        Maintains the insertion order.	1.        Slower than HashSet as it maintains the insertion order. 2.        Not thread –safe.*
TreeSet	tree	1.        Maintains the natural order among elements. 2.        You can impose different order by passing your own Comparator.	1.        Not thread –safe.*