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Groups > comp.lang.java.help > #1883

Re: A a = new B();

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On Sun, 17 Jun 2012 06:44:50 -0700 (PDT), Davej <galt_57@hotmail.com>
wrote, quoted or indirectly quoted someone who said :

>Can this be valid? If so what is this called? Thanks.

what are A and B.  A might be an interface and B a class.  A might be
a superclass or subclass of B.

Newbies tend to write code of the form

A a = new A();

Old hands tend to write code of the form

SomeInterface a = new ConcreteClass();

-- 
Roedy Green Canadian Mind Products
http://mindprod.com
If you look in a computer programmer's freezer you will find all 
kinds of containers, but none of them labeled.  They do the same thing 
creating files without labeling the encoding.  You are just supposed to 
know.  Ditto with the MIME type, the separator and comment delimiters and 
column names in CSV files.  Ditto with the endian convention.  Imagine how 
much more civilised life would have been if Martha Stewart were the first 
programmer. 

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A a = new B(); Davej <galt_57@hotmail.com> - 2012-06-17 06:44 -0700
  Re: A a = new B(); markspace <-@.> - 2012-06-17 07:55 -0700
    Re: A a = new B(); Davej <galt_57@hotmail.com> - 2012-06-17 09:23 -0700
      Re: A a = new B(); David Lamb <dalamb@cs.queensu.ca> - 2012-06-17 12:56 -0400
      Re: A a = new B(); markspace <-@.> - 2012-06-17 10:02 -0700
  Re: A a = new B(); rossum <rossum48@coldmail.com> - 2012-06-17 18:00 +0100
    Re: A a = new B(); markspace <-@.> - 2012-06-17 11:03 -0700
  Re: A a = new B(); Roedy Green <see_website@mindprod.com.invalid> - 2012-06-17 14:02 -0700
    Re: A a = new B(); Joerg Meier <joergmmeier@arcor.de> - 2012-06-19 02:31 +0200
      Re: A a = new B(); Lew <noone@lewscanon.com> - 2012-06-18 22:12 -0700
      Re: A a = new B(); Roedy Green <see_website@mindprod.com.invalid> - 2012-06-19 04:57 -0700
        Re: A a = new B(); Joerg Meier <joergmmeier@arcor.de> - 2012-06-19 14:49 +0200
          Re: A a = new B(); Gene Wirchenko <genew@ocis.net> - 2012-06-19 09:18 -0700

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