Set implementations in java

Being a Collection subtype all methods in the Collection interface are also available in the Set interface.
Since Set is an interface you need to instantiate a concrete implementation of the interface in order to use it. You can choose between the following Set implementations in the Java Collections API:

• java.util.EnumSet
• java.util.HashSet
• java.util.LinkedHashSet
• java.util.TreeSet

Each of these Set implementations behaves a little differently with respect to the order of the elements when iterating the Set, and the time (big O notation) it takes to insert and access elements in the sets