Вопрос Java. Почему не работает ввод с клавиатуры

[Kalunko]

package com.devcilibri;

import java.util.*;

public class Main {
static Scanner reader = new Scanner(System.in);
static double a = reader.nextDouble(), b = reader.nextDouble(), c = reader.nextDouble(), D, x1, x2, x;

public static void main(String[] args) {
D = b * b - (4 * a * c);
if (D > 0) {
x1 = -b + Math.sqrt(D);
x2 = -b - Math.sqrt(D);
System.out.println(x1);
System.out.println(x2);
} else if (D == 0) {
x = -b / (2 * a);
System.out.println(x);
} else {
System.out.println("Нет корней");
}
}
}

Выдает после запуска пустое пространство и введя в него число выдает:
4.5
Exception in thread "main" java.lang.ExceptionInInitializerError
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:123)
Caused by: java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:864)
at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextDouble(Scanner.java:2413)
at com.devcilibri.Main.(Main.java:7)
... 3 more

Process finished with exit code 1