TreeSet toArray() method in Java with Example

The toArray() method of Java TreeSet is used to form an array of the same elements as that of the TreeSet. Basically, it copies all the element from a TreeSet to a new array.

Syntax:

Object[] arr = TreeSet.toArray()

Parameters: The method does not take any parameters.

Return Value: The method returns an array containing the elements similar to the TreeSet.

Below programs illustrate the TreeSet.toArray() method:

Program 1:

// Java code to illustrate toArray()

import java.util.*;

public class TreeSetDemo {
    public static void main(String args[])
    {
        // Creating an empty TreeSet
        TreeSet<String>
            set = new TreeSet<String>();

        // Use add() method to add
        // elements into the TreeSet
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("For");
        set.add("Geeks");

        // Displaying the TreeSet
        System.out.println("The TreeSet: "
                           + set);

        // Creating the array and using toArray()
        Object[] arr = set.toArray();

        System.out.println("The array is:");
        for (int j = 0; j < arr.length; j++)
            System.out.println(arr[j]);
    }
}

Output:

The TreeSet: [For, Geeks, To, Welcome]
The array is:
For
Geeks
To
Welcome

Program 2:

// Java code to illustrate toArray()

import java.util.*;

public class TreeSetDemo {
    public static void main(String args[])
    {
        // Creating an empty TreeSet
        TreeSet<Integer>
            set = new TreeSet<Integer>();

        // Use add() method to add
        // elements into the TreeSet
        set.add(10);
        set.add(15);
        set.add(30);
        set.add(20);
        set.add(5);
        set.add(25);

        // Displaying the TreeSet
        System.out.println("The TreeSet: "
                           + set);

        // Creating the array and using toArray()
        Object[] arr = set.toArray();

        System.out.println("The array is:");
        for (int j = 0; j < arr.length; j++)
            System.out.println(arr[j]);
    }
}

Output:

The TreeSet: [5, 10, 15, 20, 25, 30]
The array is:
5
10
15
20
25
30