Re: How to separate interface from implementation when using JARs?

 In an engineering world where I used to be working with C++ I am
 now shiftnig to Java. In C++ I would publishe my interfaces in
 header files. In Java I can use the interface concept. However
 this is not sufficient for me. I want to be able to full separate
 the implementation from the interface of e.g. a class method.

 Example:

 public interface MyMath {
int MyAdd(int a, int n);
}

class Calculate implements MyMath {
int MyAdd(int a, int n) {
return a - b;
}

I would use this class as an import in my client code:

#import Calculate

class client {
void DoIt() {
Calculate c = new Calculate();
int sum = c.MyAdd(9,7);
}

Once I discover the implementation error in the Calculate and want
to fix that I do not want to change the client code to require
recompilation/distribution. In C++ I would not have to change the
header file,only a cpp file. I would compile and link the math
library to a dll and redistribute only that DLL. In basic JAVA, when
I recompile my client code will recompile leading to a new
(changed?) client JAR which I should also redistibute. This is
undesired for me.