java set(i) code example

Example 1: set in java

SET: Can only store unique values, 
     And does not maintain order
- HashSet can have null, order is not guaranteed
- LinkedHashSet can have null and keeps the order 
- TreeSet sorts the order and don't accept null

Example 2: set java

A Set is a Collection that cannot contain duplicate elements.
  
The Set interface contains only methods inherited from Collection 
and adds the restriction that duplicate elements are prohibited.