There is a workaround for your problem. You can use reflection to achieve it.
First, create an interface for your target class Calculatons :
package mypackage;
public interface CalculationsInterface {
int Calculate(int contextId);
double GetProgress(int contextId);
}
Next, make your target class implements that interface:
public class Calculations implements mypackage.CalculationsInterface {
@Override
native public int Calculate(int contextId);
@Override
native public double GetProgress(int contextId);
static {
System.loadLibrary("Calc");
}
}
Finally, use reflection to create an instance of Calculations class and assign it to a variable of type CalculationsInterface :
Class<?> calcClass = Class.forName("Calculations");
CalculationsInterface api = (CalculationsInterface)calcClass.newInstance();
// Use it
double res = api.GetProgress(10);