Find the index of the smallest element

The problem

Write a method that returns the index of the smallest element in an array of integers. If the number of such elements is greater than 1, return the smallest index. Use the following header: public static int indexOfSmallestElement(double[] array). Write a test program that prompts the user to enter ten numbers, invokes this method to return the index of the smallest element, and displays the index.

Breaking it down

static final int USER_NUMBERS = 10;

public static void main(String[] args) {

    Double[] numbers = new Double[USER_NUMBERS];
    Scanner input = new Scanner(System.in);

    System.out.print("Enter " + USER_NUMBERS + " numbers: ");
    for (int i = 0; i < numbers.length; i++) {
        numbers[i] = input.nextDouble();
    }
    input.close();

    System.out.println("The index of the smallest number is: "
            - indexOfSmallestElement(numbers));

}

public static int indexOfSmallestElement(Double[] array) {

    List<Double> numbersAsList = Arrays.asList(array);

    OptionalDouble minValue = numbersAsList.stream()
            .mapToDouble(Double::doubleValue).min();

    return numbersAsList.lastIndexOf(minValue.getAsDouble());
}

Output

Enter 10 numbers: 9
8
7
6
5
6
7
8
1
2
3
The index of the smallest number is: 8