public class UseNumbers {

public static double sumList(List<Number> numbers) {

// Java 7

// double total = 0;

// for (Number n : numbers) {

// total += n.doubleValue();

// }

// return total;

return numbers.stream()

.mapToDouble(Number::doubleValue)

.sum();

}

public static void main(String[] args) {

List<Number> numbers = Arrays.asList(3, 1, 4, 1, 5, 9);

System.out.println(sumList(numbers));

List<Integer> ints = Arrays.asList(3, 1, 4, 1, 5, 9);

// System.out.println(sumList(ints));

// System.out.println("line added");

//// System.out.println("2nd time added");

//added new things 1

//added new things2

//done my changes

//final copy

}

}