Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #26189

Re: Java vs C++

Show all headers | View raw

Andreas Leitgeb wrote:
> The "problem" about type-erasure is over-rated.
>
> Suppose, an instance created so: Object o = new ArrayList<String>();
> actually "knew" that it was an ArrayList of Strings (and not just
> that it was an ArrayList, as it does now).
> Then you would get a *runtime*-Error, if you tried to cast "o" to
> ArrayList<Integer>, later.  But generics aren't about runtime errors.
> They are about being able to prevent some runtime-errors, by turning
> them into compile-time errors. So, giving *still runtime*-errors for
> casting between generic types of incompatible parametrizations is only
> little win over giving runtime-errors on element-use.

I'm very glad you made that point.  I am glad we have type erasure in Java. 
It forces you to deal with type assertions at compile time.

The problem with reifiable types is that it's too easy to do a half-assed job 
of your type analysis, thus resulting in the runtime errors to which Andreas 
alludes.  Besides, all you need to do to get runtime typing is to include a 
runtime type token as a final member of your class and Bob's your uncle.  Like 
so much else in Java, that just means you have to *think* and act for 
yourself, and type a few extra lines of code.  Don't sprain your finger with 
that extra typing, whiners!

-- 
Lew
Ceci n'est pas une fenêtre.
.___________.
|###] | [###|
|##/  | *\##|
|#/ * |   \#|
|#----|----#|
||    |  * ||
|o *  |    o|
|_____|_____|
|===========|

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Java vs C++ Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-02-07 15:53 +1300
  Re: Java vs C++ Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-02-08 10:25 +0000
    Re: Java vs C++ Lew <noone@lewscanon.com> - 2011-02-08 07:53 -0500
  Re: Java vs C++ Esmond Pitt <esmond.pitt@bigpond.com> - 2011-02-08 10:26 +1100
    Re: Java vs C++ Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-02-08 16:17 +1300
      Re: Java vs C++ Esmond Pitt <esmond.pitt@bigpond.com> - 2011-02-08 16:51 +1100
  Re: Java vs C++ Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-02-06 22:06 -0500
  Re: Java vs C++ "Mike Schilling" <mscottschilling@hotmail.com> - 2011-02-06 22:42 -0800
  Re: Java vs C++ Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-02-07 21:20 -0500
  Re: Java vs C++ Arne Vajhøj <arne@vajhoej.dk> - 2011-02-06 22:07 -0500
    Re: Java vs C++ Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-02-07 19:07 +1300

csiph-web