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Groups > comp.lang.java.programmer > #36224

Re: Type conversions with the empty string

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On 30.01.2017 07:39, Joerg Meier wrote:
> On Sun, 29 Jan 2017 17:57:55 +0100, Robert Klemme wrote:
>
>> On 28.01.2017 14:43, Stefan Ram wrote:
>>>   I'd say that
>
>>> "".valueOf( 123 )
>
>>>   is even more robust than
>
>>> String.valueOf( 123 )
>
>>>   because the former is still working when a file »String.class«
>>>   is found early enough in the class path.
>> What do you mean by that?  Why would the second form be less robust?
>> This does not make any sense to me as the same class is used.
>
> Check http://ideone.com/9xXYpi
>
> 		System.out.println("" + 123);
> 		System.out.println(String.valueOf(123));
> 		
> ends up printing out:
>
> 123
> 15129

Your remark about class path mislead me.  This is not about class path 
but about namespaces.

Come on.  This is a constructed edge case for various reasons:

  - Although it is of course perfectly legal to implement a class called 
"String" in any other package someone who does that would have to have 
very good reasons to do it - especially since it makes any reference to 
java.lang.String extremely tedious.
  - Even more so as it shadows methods in java.lang.String with methods 
having the same name but incompatible semantics.
  - PrintStream.println(int) does exist, so would have been the much 
more reasonable and concise choice which does not fall into this trap.

https://docs.oracle.com/javase/8/docs/api/java/io/PrintStream.html#print-int-

Basically you are using a String constant as a shortcut for the full 
qualified class name java.lang.String.

Btw. that class could still have used java.lang.String.valueOf() and 
avoided the String constant:

class String {
   public static java.lang.String valueOf(int i) {
     return java.lang.String.valueOf(i * i);
   }
}

For me this edge case is so obscure that it does not warrant digressing 
from what a reasonable programmer would do and to avoid the use of a 
String constant here.

This case does exhibit a interesting detail of the Java compiler in 
Eclipse Mars 4.5.2: even though invocation of static methods on 
instances is set to be flagged as warning it does /not/ bark on the line 
with "" + 123.  That is odd.

Kind regards

	robert

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

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Re: Type conversions with the empty string Robert Klemme <shortcutter@googlemail.com> - 2017-01-29 17:57 +0100
  Re: Type conversions with the empty string Joerg Meier <joergmmeier@arcor.de> - 2017-01-30 07:39 +0100
    Re: Type conversions with the empty string Robert Klemme <shortcutter@googlemail.com> - 2017-01-30 10:08 +0100
      Re: Type conversions with the empty string Joerg Meier <joergmmeier@arcor.de> - 2017-02-07 09:26 +0100
        Re: Type conversions with the empty string Andreas Leitgeb <avl@logic.at> - 2017-02-07 08:34 +0000
        Re: Type conversions with the empty string lewbloch@gmail.com - 2017-02-12 11:20 -0800
          Re: Type conversions with the empty string Joerg Meier <joergmmeier@arcor.de> - 2017-02-13 08:40 +0100
            Re: Type conversions with the empty string Andreas Leitgeb <avl@logic.at> - 2017-02-13 17:38 +0000
              Re: Type conversions with the empty string Andreas Leitgeb <avl@logic.at> - 2017-02-13 17:48 +0000
                Re: Type conversions with the empty string Robert Klemme <shortcutter@googlemail.com> - 2017-02-16 10:53 +0100
                Re: Type conversions with the empty string lewbloch@gmail.com - 2017-02-19 02:42 -0800
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-19 08:45 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 09:20 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 09:21 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-19 10:51 -0500
                Re: Type conversions with the empty string Robert Klemme <shortcutter@googlemail.com> - 2017-02-19 19:55 +0100
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-19 15:55 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 23:31 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 08:39 -0500
                Re: Type conversions with the empty string Eric Douglas <e.d.programmer@gmail.com> - 2017-02-20 06:10 -0800
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 09:54 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 10:25 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 11:02 -0500
                Re: Type conversions with the empty string Eric Douglas <e.d.programmer@gmail.com> - 2017-02-20 08:45 -0800
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 14:46 -0500
                Re: Type conversions with the empty string Eric Douglas <e.d.programmer@gmail.com> - 2017-02-20 12:23 -0800
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 16:31 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 11:58 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 14:46 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 15:45 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 15:54 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 20:31 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 09:13 -0500
                Re: Type conversions with the empty string Martin Gregorie <martin@address-in-sig.invalid> - 2017-02-19 14:43 +0000
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 10:11 -0500
                Re: Type conversions with the empty string Martin Gregorie <martin@address-in-sig.invalid> - 2017-02-19 15:20 +0000
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-19 10:53 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-19 23:24 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 08:43 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 10:16 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 11:03 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 12:00 -0500
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-20 14:49 -0500
                Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-20 15:47 -0500
                Re: Type conversions with the empty string lewbloch@gmail.com - 2017-02-20 22:18 -0800
                Re: Type conversions with the empty string Jerry Stuckle <jstucklex@attglobal.net> - 2017-02-21 08:23 -0500
            Re: Type conversions with the empty string lewbloch@gmail.com - 2017-02-19 02:39 -0800
        Re: Type conversions with the empty string Arne Vajhøj <arne@vajhoej.dk> - 2017-02-13 12:46 -0500

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