Re-Implementation Versus Overriding

[Brandon Tom]

This is something straight from the ePractice exam that seemed a bit like a trick question, but let me make sure I've got the idea down right.

In the Heller and Roberts book "Complete Java 2 Study Guide, Fifth Edition" it says that final, when applied to a method, does not allow it to be overridden, so when I came across this question:

1. class Book {
2.   private final void read() { System.out.print("book "); }
3. }
4. class Page extends Book {
5.   public static void main(String [] args) {
6.     // insert code here
7.   }
8.   private final void read() { System.out.print("page "); }
9. }

I would think that Book would cause a compilation error. However, Page.read () isn't an override, it's a reimplementation. If I removed the 'final' it would then become and override and then it would break. Is that correct?
[ January 25, 2006: Message edited by: Brandon Tom ]

[Jay Pawar]

Originally posted by Brandon Tom:

If I removed the 'final' it would then become and override and then it would break. Is that correct?

Even if you remove the final keyword, the methods are private and private methods are not inherited. So there is no question of overriding them.
Hope I didn't confuse you...

[ven kaar]

bcos, the method 'read()'is marked as private final in Book class, the page class method 'read()' probably is reimplementation.

if u try removing private in Book class, Page class will not compile as method 'read()' stands final.

public class Book {
final void read() { System.out.print("book "); }
}

[ven kaar]

bcos, the method 'read()'is marked as private final in Book class, the page class method 'read()' probably is reimplementation.

if u try removing private in Book class, Page class will not compile as method 'read()' stands final.

public class Book {
final void read() { System.out.print("book "); }
}
 
public class Page extends Book {
public static void main(String[] in) {
Page page = new Page();
page.read();
}
final void read() { System.out.print("Page "); }
}

anyway , i am not sure whether it is reimplementation(first time i am hearing this)

[Brandon Tom]

I see, so it's the 'private' declaration that is the key here, not the word final. I see, thanks for the input.