Implementing interfaces

[Tomek Kaczmarek]

Folks,
I'm working with APress SCJP exam book.
In the final test I found one qeustion(No 7 in final test):

1. interface Animal {
2. void saySomething();
3. }
4. class farm {
5. void setName(String name){};
6. }
7. // insert code here
8. public class Cow implements Pasture {
9. public void graze() { }
10. void saySomething(){}
11.}
Which of the following code lines inserted independently at line 7 will make this source file compile?
A. interface Pasture {void graze();}
B. interface Pasture {void graze(){}}
C. interface Pasture extends Animal{void graze();}
D. interface Pasture extends Animal{void saySomething(){}}
E. interface Pasture implements Animal{void graze();}

What are your candidates?
B and D is wrong because you cannot implement a method in interface.
E is wrong because interface can extends not implement another interface.
A is OK.
How about C? It looks good but when we look carefully we can see that in Cow class the method saySomething is marked as a default.
This method is also declared in Animal interface, also without any word about public. But all methods, variables in interfaces are public.
So C is not correct because if Pasture implement Animal than the Cow class will not compile.
Please correct me if I'm wrong.

Thanks,
Tomek

[Kinnaree Patel]

Originally posted by Tomek Kaczmarek:
Folks,
I'm working with APress SCJP exam book.
In the final test I found one qeustion(No 7 in final test):


What are your candidates?
B and D is wrong because you cannot implement a method in interface.
E is wrong because interface can extends not implement another interface.
A is OK.
How about C? It looks good but when we look carefully we can see that in Cow class the method saySomething is marked as a default.
This method is also declared in Animal interface, also without any word about public. But all methods, variables in interfaces are public.
So C is not correct because if Pasture implement Animal than the Cow class will not compile.
Please correct me if I'm wrong.

Thanks,
Tomek

Yes, Tomek. Thats right. We cannot have the weaker access in class than in interface.

[Mohit Jain]

Yep the answer must be A.

[Pankaja Shinde]

you are right