TreeSet is one of the implementations of the Navigable sub-interface. It is underlying data structure is a red-black tree. The elements are stored in ascending order and more methods are available in TreeSet compare to SortedSet. We can also change the sorting parameter using a Comparator. For example, Comparator provided at set creation time, depending on which constructor is used.
- It also implements NavigableSet interface.
- NavigableSet extends SortedSet and Set interfaces.
Example
Java
// Java Program to Illustrate TreeSetÂ
// Importing required classesimport java.util.*;Â
// Main classclass GFG {Â
    // Main driver method    public static void main(String args[]) {Â
        // Creating an empty TreeSet of string type elements        TreeSet<String> al = new TreeSet<String>();Â
        // Adding elements        // using add() method        al.add("Welcome");        al.add("to");        al.add("Geeks for Geeks");Â
        // Traversing elements via help of iterators        Iterator<String> itr = al.iterator();Â
        // Holds true until there is element remaining in object        while (itr.hasNext()) {Â
            // Moving onto next element with help of next() method            System.out.println(itr.next());        }    }} |
Geeks for Geeks Welcome to
Sorted Set
The SortedSet is a sub-interface, which is available in java.util.package which extends the Set interface. This interface contains the methods inherited from the Set interface. For example, headSet, tailSet, subSet, Comparator, first, last, and many more.
Example
Java
// Java program to Illustrate SortedSetÂ
// Importing utility classesimport java.util.*;Â
// Main classclass GFG {Â
    // Main driver method    public static void main(String[] args)    {Â
        // Creating an instance of SortedSet        // String type        SortedSet<String> ts = new TreeSet<String>();Â
        // Adding elements into the TreeSet        // using add()        ts.add("Sravan");        ts.add("Ojaswi");        ts.add("Bobby");        ts.add("Rohith");        ts.add("Gnanesh");        ts.add("Devi2");Â
        // Adding the duplicate element        // again simply using add() method        ts.add("Sravan");Â
        // Print and display TreeSet        System.out.println(ts);Â
        // Removing items from TreeSet        // using remove() method        ts.remove("Ojaswi");Â
        // Display message        System.out.println("Iterating over set:");Â
        // Iterating over TreeSet items        Iterator<String> i = ts.iterator();Â
        // Condition holds true till there is single element        // remaining in the object        while (i.hasNext())Â
            // Printing elements            System.out.println(i.next());    }} |
[Bobby, Devi2, Gnanesh, Ojaswi, Rohith, Sravan] Iterating over set: Bobby Devi2 Gnanesh Rohith Sravan
Now after having adequate understanding and internal working of both TreeSet and SortedSet, now let us see the differences between TreeSet and SortedSet which is as depicted from the table provided below as follows:
| Basis |
TreeSet |
SortedSet |
|---|---|---|
| Classification | Class of NavigableSet sub-interface. | Sub-Interface |
| Insertion Order | TreeSet maintains an object in sorted order. | SortedSet maintains an object in sorted order. |
| Initialization |
Syntax: TreeSet<Datatype> treeset = new TreeSet<>(); |
Syntax: It can not be instantiated as it is a sub-Interface. |
| Methods | Contains more methods than SortedSet. | Contains fewer methods than TreeSet. |
| Example | contains all the methods of SortSet. In addition methods like ceiling(), floor(), higher(), lower() and e.t.c | contains methods like add(), addAll(), iterator(), retainAll() and e.t.c |
Conclusion: Basically in simple words let’s assume this way, TreeSet is a class of NavigableSet which contains all of the methods for better traversing and searching for values. SortedSet is a sub-set of NavigableSet in terms of methods compare to TreeSet(NavigableSet)
