请说出E类中【代码1】，【代码2】的输出结果。interface A { double f(double x,double y); }class B implements A { public double f(double x,double y) { return x*y; } int g(int a,int b) { return a+b; }}public class E {public static void main(String args[]) { A a = new B(); System.out.println(a.f(3,5)); //【代码1】 B b = (B)a; System.out.println(b.g(3,5)); //【代码2】 }}