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Re: When to use dynamic binding over dynamic dispatch?

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On 08.05.2016 16:37, Arne Vajhøj wrote:
> On 5/8/2016 8:57 AM, Eric Sosman wrote:
>> On 5/8/2016 8:23 AM, Arne Vajhøj wrote:
>>> On 5/8/2016 6:24 AM, Robert Klemme wrote:
>>>> On 04.05.2016 03:23, Arne Vajhøj wrote:
>>>>> All methods unless declared static or final are virtual in Java,
>>>>> so dynamic dispatch is used all the time.
>>>>
>>>> Methods declared as "final" are virtual as well.
>>>
>>> Given that:
>>>
>>> virtual method = method that can be overridden
>>> final method = method that can not be overridden
>>>
>>> then how can it be?
>>
>>     class Super {
>>         public void method() {}
>>     }
>>
>>     class Sub extends Super {
>>         public final void method() {}
>>     }
>>
>>     ...
>>
>>     Super obj = new Sub();
>>     obj.method();
>
> As a starting point I would not call Sub.method
> a virtual method due to above definition.

That seems to me a fairly uncommon definition.  For me a virtual method 
uses dynamic dispatch (late binding) as described in Wikipedia:
https://en.wikipedia.org/wiki/Virtual_method

> But per JLS such calls are "invocation mode virtual".

Hence it's a virtual method in my book.

> If we make the logical conclusion that methods that will be called
> with invocation mode virtual are virtual methods, then the definition
> of virtual methods is certainly different in Java.

Certainly different from the definition you offered above.  Ironically 
your first statement matches the definition of "virtual method" that I 
have in mind much better because it speaks of "dynamic dispatch", i.e. 
does not make a statement about whether it can be overridden and instead 
focuses on invocation semantics.

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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When to use dynamic binding over dynamic dispatch? cdalten@gmail.com - 2016-05-02 18:08 -0700
  Re: When to use dynamic binding over dynamic dispatch? Sebastian <news@seyweiler.dyndns.org> - 2016-05-03 20:47 +0200
    Re: When to use dynamic binding over dynamic dispatch? Lew <lewbloch@gmail.com> - 2016-05-03 12:14 -0700
  Re: When to use dynamic binding over dynamic dispatch? Arne Vajhøj <arne@vajhoej.dk> - 2016-05-03 21:23 -0400
    Re: When to use dynamic binding over dynamic dispatch? Martin Gregorie <martin@address-in-sig.invalid> - 2016-05-04 10:48 +0000
    Re: When to use dynamic binding over dynamic dispatch? Robert Klemme <shortcutter@googlemail.com> - 2016-05-08 12:24 +0200
      Re: When to use dynamic binding over dynamic dispatch? Arne Vajhøj <arne@vajhoej.dk> - 2016-05-08 08:23 -0400
        Re: When to use dynamic binding over dynamic dispatch? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-08 08:57 -0400
          Re: When to use dynamic binding over dynamic dispatch? Arne Vajhøj <arne@vajhoej.dk> - 2016-05-08 10:37 -0400
            Re: When to use dynamic binding over dynamic dispatch? Robert Klemme <shortcutter@googlemail.com> - 2016-05-08 22:30 +0200
              Re: When to use dynamic binding over dynamic dispatch? Arne Vajhøj <arne@vajhoej.dk> - 2016-05-08 23:08 -0400
                Re: When to use dynamic binding over dynamic dispatch? Robert Klemme <shortcutter@googlemail.com> - 2016-05-09 08:16 +0200
            Re: When to use dynamic binding over dynamic dispatch? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-08 16:44 -0400
              Re: When to use dynamic binding over dynamic dispatch? Arne Vajhøj <arne@vajhoej.dk> - 2016-05-08 23:16 -0400
                Re: When to use dynamic binding over dynamic dispatch? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-09 00:39 -0400

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