Hi Srini, It may be array or some other Object type where it might not be possible to impose "final" you know if we really want "immutablility" by any child classes. Final just makes reference not changeable but we can still change values within that object via setters or something if we have any mutator methods. So in that case it ...
I can't think of any reason for a blanket statement like that. Don't know what this "Complete" book is, but if you have a book that makes claims like this without explaining them, I'd use it for kindling. If the book includes an explanation and you'd like help understanding it, please share it with us!