Q:

Average Calculating Program Issue

I've just started learning Java, and I'm pretty confused at this point.  I'm trying to make a program that will average out any amount of numbers that the user would input, but I can't figure out how to allow the user to input as many numbers as they want.  Right now, the code just lets them do 1 number before it averages. 
Notes:
There's a good chance I'm writing this totally wrong, I'm doing this to see what I know so far
I use Eclipse
I'm learning from www.thenewboston.org
Here's the code:
import java.util. Scanner;

class MainClass {
    public static void main(String[] args){
        System.out.println("Enter Grades Now");
        Scanner input = new Scanner(System.in);
        double input2 = input.nextDouble();

        System.out.println(average(input2));
    }

    public static double average(double...numbers){
        double total=0;
        for(double x:numbers)
            total+=x;

        return total/numbers.length;
    }

}

A:

You can use a LinkedList<Double> and a loop to let the user input an artificial amount of numbers. 
Scanner input = new Scanner(System.in);
List<Double> allDoubles = new LinkedList<Double>();

do {
    System.out.print("Next grade: ");
    allDoubles.add(input.nextDouble());
} while (input.hasNextDouble());

System.out.println(average(allDoubles.toArray(new Double[0])));

Enter as many values as you like and then enter some text like "done".