How to Add or Append Elements to End of a TreeSet in Java?

A TreeSet is a sorted set implementation of the Set interface based on a TreeMap. It uses a Red-Black tree to store elements. Elements are sorted according to their natural ordering, or a custom Comparator provided at the time of TreeSet creation.

• It does not allow duplicate elements or null values.
• It provides log(n) time complexity for basic operations like add, remove, and contains due to its tree implementation.
• Common methods include add(), remove(), contains(), first(), last(), lower(), higher() etc.

In this article, we will learn about how to add elements to the end of a TreeSet in Java.

Syntax:

TreeSet.add(object element)

Program to add elements to the end of a TreeSet in Java

Below is the implementation to append elements to the end of a TreeSet.

Java

// Java Program to add elements to the end of a TreeSet
import java.util.TreeSet;
public class TreeSetExample
{
    public static void main(String[] args)
    {
        // Create a TreeSet
        TreeSet<String> courseSet = new TreeSet<>();

        // Add elements to the TreeSet
        courseSet.add("Java");
        courseSet.add("Python");
        courseSet.add("C++");

        // Print the TreeSet
        System.out.println("TreeSet elements: " + courseSet);

        // Add elements to the end of TreeSet
        courseSet.add("DSA");
        courseSet.add("Full Stack Web Development");

        // Print the TreeSet after adding elements
        System.out.println("TreeSet elements after adding: " + courseSet);
    }
}

Output

TreeSet elements: [C++, Java, Python]
TreeSet elements after adding: [C++, DSA, Full Stack Web Development, Java, Python]

Explanation of the Program:

• In the above program, a TreeSet of Strings is created to store course names.
• Some course names are added to the TreeSet which sorts them automatically.
• The initial TreeSet elements are printed in sorted order.
• More courses are added and TreeSet keeps them sorted in insertion order.
• The final TreeSet after all additions is printed, still maintaining sorted order.

Note: TreeSet is automatically sorted, so the final output shows the elements in their natural order.