Simple java inheritance question

Question

Is it possible to extend the Math class and still use the Math class to call the extended method?

For example, I have a method public static double mean (LinkedList<? extends Number) I would like to call like this Math.mean(list). Is this doable? How?

Thanks.

Answer 1

Doc Java.lang.Math is Final class, can't be extended
Update: Static Method can't be inherited & final class can't be extended.

Answer 2

You can't subclass the Math class because it's final. You could use composition i.e. write your own wrapper class but there wouldn't be much point in that because all of Math's methods are static.

Answer 3

Even if Math wasn't final, you couldn't do this. You can't use a superclass to call a function defined in a subclass. By definition, a subclass has access to all non-private methods defined in the superclass, but a superclass does not have access to functions in a subclass.

Answer 4

A workaround could be to create your own Math class and use java.lang.Math as composite. The methods without any change can just be delegated to original methods in java.lang.Math. You could rewrite the methods you want to change or expose new methods in your Math class.

The code look like:

public class YourMath {  
  public static double mean(LinkedList) {
     //Your new method
  }
  public static double abs(double a) {
     return Math.abs(a); //Delegate
  }
  //...... Any other methods
}