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From: Jim Janney <jjanney@shell.xmission.com>
Newsgroups: alt.comp.lang.borland-delphi,comp.lang.c,comp.lang.java.programmer
Subject: Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;)
Date: Wed, 23 May 2012 08:46:57 -0600
Organization: he sent them word I had not gone
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References: <b3f1b$4fb4f87c$5419acc3$14079@cache60.multikabel.net> <jpht7l$vnj$2@blue-new.rahul.net>
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falk@rahul.net (Edward A. Falk) writes:

> In article <b3f1b$4fb4f87c$5419acc3$14079@cache60.multikabel.net>,
> Skybuck Flying <Windows7IsOK@DreamPC2006.com> wrote:
>>
>>"
>>private static void rangeCheck(int arrayLen, int fromIndex, int toIndex) {
>>    if (fromIndex > toIndex)
>>        throw new IllegalArgumentException("fromIndex(" + fromIndex +
>>                   ") > toIndex(" + toIndex+")");
>>    if (fromIndex < 0)
>>        throw new ArrayIndexOutOfBoundsException(fromIndex);
>>    if (toIndex > arrayLen)
>>        throw new ArrayIndexOutOfBoundsException(toIndex);
>>}
>>"
>
> Executive summary:  If the indices here are used as [fromIndex toIndex) --
> that is, inclusive-exclusive -- as is often the custom, *and* a
> zero-length range is permitted, then this code is correct as written.
>
> Plus, if this was a commonly-used code fragment, any error would have
> turned up long ago.
>
> Finally, the keyword "private" means that this function is unavailable
> outside of the file that defines it.  There would be no reason to document
> it.  There would also be no reason to hold it to any standard other than
> that it perform the specific function for which it was intended.  Without
> seeing the functions or methods that call it, there's really no true way
> to know if it's buggy or not.

The complete code is available for inspection: it's distributed with
every copy of the JDK, and can also be found on the web at many places,
for example:

http://cr.openjdk.java.net/~martin/webrevs/openjdk7/timsort/src/share/classes/java/util/TimSort.java.html

And as has been pointed out before, the function *is* documented and the
implementation matches its contract exactly.

It's not a bug.  Period.

-- 
Jim Janney