Problem 8.**Get Average

Create a method that finds the average of three numbers. Read in internet about java methods. Check the naming conventions. Invoke your method and test it. Format the output to two digits after the decimal separator. The placeholder is %.2f

import java.util.Scanner;

public class _8_01_GetAverage {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double a = scanner.nextDouble();
        double b = scanner.nextDouble();
        double c = scanner.nextDouble();
        getAverage(a, b, c);
    }

    public static void getAverage(double a, double b, double c) {
        double sum = (a + b + c) / 3;
        System.out.printf("%.2f", sum);
    }
}

Всичко прави, но вместо  да работи с десетична точка 1.5 / 2.5 / 3.8  тя  работи с десетична запетая 1,5 / 2,5 /3,8! Какво да променя или да допиша ...?