Hi,

I am doing some scientific programming using Java. I have a static
method doing some calculation. To help its calculation, I hope to have a
class Helper inside the method doing some routine, modular calculation.
But I ran into 2 problems. Could you help me out? Thank you very much.

==============Subroutines.java===========
class MyClass
{
    public double A, B;
}

public class Subroutines
{

    public static double getValue(MyClass obj)  //Question 1: I need "final
MyClass obi", why? Because inside the method, obj needs to be
modified/updated, adding final will prevent it be changed or not?
    {
        class Helper  //Question 2: I hope it can be static, so I can
Helper.getDiff(), instead of new Helper().getDiff(). But my compiler
won't let me do it.
        {
            public static double getDiff()
            {
                retunr (obj.A-obj.B);

            }
        }

        //start doing calculation
        Helper helper = new Helper();
        ...//code for doing calculation. I simplified here in the posting
        return helper.getDiff();
    }

}