Odd file.exists() problem

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O.B. - 27 Jan 2006 22:51 GMT

I'm hoping there is just something syntactically wrong with the
following. I've verified that the file exists, but it keeps saying that
it doesn't. Thoughts?

String filename = "C:\\Java\\j2sdk1.4.2_10\\jre\\bin\\java";
File testFile = new File(filename);
if (testFile.exists()) {
System.out.println(filename + " exists.");
} else {
System.out.println(filename + " does not exist.");
}

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Oliver Wong - 27 Jan 2006 22:54 GMT

> I'm hoping there is just something syntactically wrong with the following.
> I've verified that the file exists, but it keeps saying that it doesn't.
[quoted text clipped - 7 lines]
> System.out.println(filename + " does not exist.");
> }

Might you be thinking "java.exe" instead of "java"?

- Oliver

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O.B. - 27 Jan 2006 22:54 GMT

> I'm hoping there is just something syntactically wrong with the
> following. I've verified that the file exists, but it keeps saying that
[quoted text clipped - 7 lines]
> System.out.println(filename + " does not exist.");
> }

Darn ... I hit send too early. My UNIX background got the best of me;
I'm missing ".exe". Argh!

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Knute Johnson - 28 Jan 2006 00:38 GMT

>> I'm hoping there is just something syntactically wrong with the
>> following. I've verified that the file exists, but it keeps saying
[quoted text clipped - 10 lines]
> Darn ... I hit send too early. My UNIX background got the best of me;
> I'm missing ".exe". Argh!

You've probably just typed something wrong somewhere. Since you are a
unix fan you can use the / instead of the \\.

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Knute Johnson
email s/nospam/knute/

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Raymond DeCampo - 30 Jan 2006 14:46 GMT

>>> I'm hoping there is just something syntactically wrong with the
>>> following. I've verified that the file exists, but it keeps saying
[quoted text clipped - 13 lines]
> You've probably just typed something wrong somewhere. Since you are a
> unix fan you can use the / instead of the \\.

Only if you want to break any routine that depends on File.separator.

Ray

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Chris Uppal - 30 Jan 2006 15:31 GMT

> > You've probably just typed something wrong somewhere. Since you are a
> > unix fan you can use the / instead of the \\.
>
> Only if you want to break any routine that depends on File.separator.

Any routine that depends carelessly on File.separator being the /only/
allowable path separator for the platform is already broken.

'/' has been a legal path separator on M$-ware since at least MS-DOS 3.

Incidentally, the Sun implementation of File normalises paths to use '\\'
throughout (on Windows). That's probably a good idea, since otherwise
File.separator would be totally useless rather than merely dangerously
misleading. But I don't know if it is documented to do so; if not then relying
on that aspect of its behaviour may not be justifiable in production code.

-- chris

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Dimitri Maziuk - 30 Jan 2006 17:22 GMT

Chris Uppal sez:

>> > You've probably just typed something wrong somewhere. Since you are a
>> > unix fan you can use the / instead of the \\.
[quoted text clipped - 11 lines]
> misleading. But I don't know if it is documented to do so; if not then relying
> on that aspect of its behaviour may not be justifiable in production code.

I don't know what File normalises paths to, but IME
"some/path/some/file" works on both unix and winders whereas
"\\some\\path\\some\\file" is M$-only. Handy when you want to
read paths from a properties file.

Another undocumented trick is "java foo/bar/MyClass" -- you can
use tab-completion on unix command line.

Dima

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Backwards compatibility is either a pun or an oxymoron. -- PGN

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Roedy Green - 30 Jan 2006 22:04 GMT

On Mon, 30 Jan 2006 14:46:37 GMT, Raymond DeCampo
<nospam@twcny.rr.com> wrote, quoted or indirectly quoted someone who
said :

>>>> String filename = "C:\\Java\\j2sdk1.4.2_10\\jre\\bin\\java";

your file is called "java..exe" not "java"

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Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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Daniel Dyer - 27 Jan 2006 22:54 GMT

I think you are missing the file extension. Shouldn't it be "java.exe"?
If you are viewing the directory in Windows Explorer it hides known file
extensions by default.

Dan.

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Daniel Dyer
http://www.dandyer.co.uk

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Odd file.exists() problem

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