Question 147: Inheritance

Given:

1. public interface A {
2. public void doSomething(String thing);
3. }

1. public class AImpl implements A {
2. public void doSomething( String msg ) {}
3. }

1. public class B {
2. public A doit() {
3. // more code here
4. }
5. 
6. public String execute() {
7. // more code here 
8. }
9. }

1. public class C extends B {
2. public AImpl doit() {
3. // more code here
4. }
5. 
6. public Object execute() {
7. // more code here 
8. }
9. }

Which of the statement is true about the classes and interfaces?

A. Compilation will succeed for all classes and interfaces.
B. Compilation of class C will fail because of an error in line 2.
C. Compilation of class C will fail because of an error in line 6.
D. Compilation of class AImpl will fail because of an error in line 2.