Re: Why can't static methods be overridden?

From: Owen Jacobson (angstrom_at_lionsanctuary.net)
Date: 09/22/04

  • Next message: Owen Jacobson: "Re: Obtaining derived classes" 
    Date: Wed, 22 Sep 2004 07:29:32 GMT

    On Tue, 21 Sep 2004 22:10:19 -0700, bernd_no_junk wrote:

    > Quite often I have a hierarchy of classes where
    > I want a specific accessor method to be
    > present in all classes. Therefore I specify
    > it in the base class. But the information
    > that this function returns only depends on the
    > actual class, so it should static, shouldn't it?
    >
    > I ran into the neccessity to do so sometimes
    > during design and started wondering why Java
    > actually forbids it.
    >
    > Is there a specific OO reason?

    This seems to be related to the recent discussion about invoking static
    methods through instances. Consider if derived classes could override
    static (class-scope) methods:

    class A {
      static void something () {}
    }

    class B extends A {
      static void something () {}
    }

    ...
      A anA = new B ();
      anA.something (); // This is valid, modulo B.something ()'s existence

    Which 'something' should be invoked, here? Currently the rules say that
    A.something should be invoked, but if it were possible to override
    something in derived classes you can bet people would then want to be able
    to call derived static methods through base class references, which I can
    only assume the Sun guys feel is much less straightforward than the
    current mechanism.

    For what it's worth I agree with them. 

    -- 
Some say the Wired doesn't have political borders like the real world,
but there are far too many nonsense-spouting anarchists or idiots who
think that pranks are a revolution.
  • Next message: Owen Jacobson: "Re: Obtaining derived classes"

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