ArrayList toArray() method in Java with Examples

The toArray() method of ArrayList is used to return an array containing all the elements in ArrayList in the correct order.

Declaring toArray() method

public Object[] toArray()
           
           or
           
public <T> T[] toArray(T[] a)

Parameters: This method either accepts no parameters or it takes an array T[] as a parameter which is the array into which the elements of the list are to be stored if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Return Value: The function returns an array containing all the elements in this list.

Exception: The first overload of this method throws no exceptions. However, the second overload throws the following exceptions:

• ArrayStoreException: if the runtime type of the specified array is not a supertype of the runtime type of every element in this list.
• NullPointerException if the specified array is null

Examples of Java ArrayList.toArray() method

Example 1

Java

// Java Program to illustrate the
// ArrayList toArray() method in Java

import java.util.*;

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

        // create object of ArrayList
        ArrayList<Integer> ArrLis
            = new ArrayList<Integer>();

        // Add elements
        ArrLis.add(32);
        ArrLis.add(67);
        ArrLis.add(98);
        ArrLis.add(100);

        // print ArrayList
        System.out.println("ArrayList: " + ArrLis);

        // Get the array of the elements
        // of the ArrayList
        // using toArray() method
        Object[] arr = ArrLis.toArray();

        System.out.println("Elements of ArrayList"
                           + " as Array: "
                           + Arrays.toString(arr));
    }
}

Output

ArrayList: [32, 67, 98, 100]
Elements of ArrayList as Array: [32, 67, 98, 100]

Example 2

Java

// Java Program to illustrate the
// ArrayList toArray(T[]) method in Java

import java.util.*;

// Driver Class
public class GFG {
    // main function
    public static void main(String[] args)
    {
        // create object of ArrayList
        ArrayList<Integer> ArrLis
            = new ArrayList<Integer>();

        // Add elements
        ArrLis.add(32);
        ArrLis.add(67);
        ArrLis.add(98);
        ArrLis.add(100);

        // print ArrayList
        System.out.println(" ArrayList: " + ArrLis);

        // Get the array of the elements
        // of the ArrayList
        // using toArray(T[]) method
        Integer arr[] = new Integer[ArrLis.size()];
        arr = ArrLis.toArray(arr);

        System.out.println(" Elements of ArrayList "
                           + "as Array: "
                           + Arrays.toString(arr));
    }
}

Output

 ArrayList: [32, 67, 98, 100]
 Elements of ArrayList as Array: [32, 67, 98, 100]