TreeSet and ConncurrentSkipListSet are two implementation classes of the interface.
Syntax:

NavigableSet<T> navigableSet = new TreeSet<>();

How to create object of NavigabelSet ?

Navigable Set is an interface, in order to create an object of that type, it is compulsory to have a implementation class of the respective interface. In this case, TreeSet can be used to create instance that can be assigned to NavigableSet type.

program:

public class SetExample {
public static void main(String[] args) {

NavigableSet<String> navigableSet = new TreeSet<>();
// Adding elements to navigableSet set object
navigableSet.add("Example");
navigableSet.add("Code");
navigableSet.add("A");

// Displaying the output
System.out.println(navigableSet);

}
}

Output:

[A, Code, Example]

It also allows a set to traverse in both orders, either ascending using an iterator or descending order with the method descendingSet(). Considering performance-wise, traversing elements in ascending order is faster than the traversing descending order. There are some more additional methods namely pollFirst() and pollLast() to remove the first and last element (lowest and highest element) from the set and return it.

Methods of NavigableSet Interface

Below are the methods that is offered by NavigableSet interface

Below are the methods that is inherited from SortedSet.

Below are the methods that is inherited Set.