Doubt in interface reference

Question

Select two correct statements about the code given below?
class A{}
class B extends A implements E{} //line 1
class C extends A{}
class D extends B{}
interface E{}
class Question07 {
public static void main(String[] args) {
A a = new D(); //line 2
C c = new C(); //line 3
E e = (E)a; //line 4
B b = e; //line 5
}Options
a. The code compiles without error and runs fine
b. Compilation error on line 1 because interface E is not yet declared (forward-referencing)
c. Compilation error on line 4 because class A does not implement interface E
d. The cast on line 4 is mandatory
e. The cast on line 5 is not mandatory
the answer is a,d,e three answers ! all answers understood except d option
how we can make E reference with casting A , and A is not implement E !!!
help me please
Message was edited by:
eaaje
Message was edited by:
eaaje

Answer 1

The type of variable a is A. Since A does not implement E, to assign a to a variable of type E you must cast it.