In java, is there ever a case for allowing a non-abstract class to be extended?
It always seems to indicate bad code when there are class hierarchies. Do you agree, and why/ why not?
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In java, is there ever a case for allowing a non-abstract class to be extended?
It always seems to indicate bad code when there are class hierarchies. Do you agree, and why/ why not?
I agree with Jon and Kent but, like Scott Myers (in Effective C++), I go much further. I believe that every class should be either
abstract, orfinal. That is, only leaf classes in any hierarchy are really apt for direct instantiation. All other classes (i.e. inner nodes in the inheritance) are “unfinished” and should consequently beabstract.It simply makes no sense for usual classes to be further extended. If an aspect of the class is worth extending and/or modifying, the cleaner way would be to take that one class and separate it into one
abstractbase class and one concrete interchangeable implementation.