Adding two generic number types

Question

Hi all,
As a small exercise I am trying to devise a generic maths class that can add two numbers together either Integer, Float and Double types.
I have written the following code
class Test {
public static void main(String args[]) {
     MathClass<Integer> integers = new MathClass<Integer>();
     Integer i= new Integer(2);
     System.out.println(integers.add(i,i));
class MathClass<T> {
     public T add(T a, T b) {
          return a + b;
     public T subtract(T a, T b) {
          return a - b;
     public T multiply(T a, T b) {
          return a * b;
     public T divide(T a, T b) {
          return a / b;
}But I get a compile error which says that I can't use the + - * / operators on T.
Yet something like the following code works
public class Test2 {
   public static void main(String[] args) {
     Integer i = new Integer(2);
     Integer o = new Integer(2);
     System.out.println(i + o);
}Is there a way to make the generic maths class work as I would like?

Answer 1

Even with the UpperBound as Number it will not be able to work as the compiler will not be able to apply autoboxing feature with Number. Number class has byteValue(), intValue(), floatValue() and doubleValue() as method, so Number class is not a spefic datatype class.
This will work because of the feature autoboxing.
public Integer addInteger(Integer a, Integer b) {
          return a + b;
This will not work...
     public Number addInteger(Number a, Number b) {
          return a + b;
     }