Finalize ()

[Shah Chunky]

Hello all...
Finalize()
This is from Khalid Mughal book:- page 256 q 8.4
True or False:-
"An Overriding Finalize method in any classs can always throw Checked Exceptions"
The Answer Given was False* Reason:- page 844.
"The finalize() in Object can throw any throwable object Overridding method can limit the range of throwable to
unchecked Exceptions. Further Overridden definitions of this method in subclass will not be able to
throw checked Exception."
But i tried Overriding finalize() with a Checked Exception:-
public void finalize() throws ClassNotFoundException
{
System.out.println("Finalize Called ");
}
The above code works properly
So what am i missing. ?
Thanks

[William Brogden]

When you override a method that throws a checked exception, your overriding method can not declare a more general exception.
The extension of this is that when you override a method that does not throw any checked exception, the overriding method can't throw a checked exception.
I bet your test case did not exactly represent the class hierarchy that KM was describing.
Bill

------------------
author of:

• Java 2 Exam Prep
  
• Java 2 (Exam Cram)
  
• Java Developer's Guide to Servlets and JSP
  
• Java Developer's Guide to E-Commerce with XML and JS
  

[Shah Chunky]

Dear Sir...
The Signature of finalize() as given in object class is :-
protected void finalize() throws Throwable
Now from above if i override the method with a Checked
Exception it works ...
But acc to KM it was given false.
Correct me if i m wrong
Thanks

[William Brogden]

I believe the situation referred to can be represented as:
Object
+-- firstDerived
+--- secondDerived
Now - if the finalize method in firstDerived does NOT declare any thrown checked exception, then the finalize in secondDerived may not declare any checked exception.
What you appear to be thinking about is:
Object
+---- firstDerived
But that is not the situation in the original question - (my addition):
"The finalize() in Object can throw any throwable object Overridding method (firstDerived) can limit the range of throwable to unchecked Exceptions. Further Overridden (secondDerived) definitions of this method in subclass will not be able to throw checked Exception."
Bill

------------------
author of:

• Java 2 Exam Prep
  
• Java 2 (Exam Cram)
  
• Java Developer's Guide to Servlets and JSP
  
• Java Developer's Guide to E-Commerce with XML and JS
  

[William Brogden]

arg - I forgot this damn system removes leading spaces.
Object
...+--- firstDerived
.........+---- secondDerived
is what I wanted to show.

[Shah Chunky]

Thanks for the Reply...