Groups > comp.lang.java.programmer > #10438

Re: java.io.File

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From	Lew <lewbloch@gmail.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: java.io.File
Date	Fri, 2 Dec 2011 14:07:57 -0800 (PST)
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Mayeul wrote:
>Lew wrote:
>> Mark wrote:
>>> Can a java.io.File object use a OS file descriptor?  I am trying to
>>> find the source of a fd leak in a[n] application.
>>
>> At some point, depending on the operations performed by the 'File' instance, there may be a file descriptor involved, and then the 'File' instance certainly does use it, at least indirectly via JVM system calls that proxy to OS system calls.
> 
> It was my understanding that java.io.File instances were merely 
> representations of pathnames, and are neither closed nor opened, just 
> places and names where files could exist or not.

How, then, do calls like 'File#canRead()', 'canWrite()', 'createNewFile()', 'createTempFile()', 'delete()', 'exists()', 'getFreeSpace()', 'isDirectory()', 'isFile()', 'list()', 'listFiles()', 'mkdir()', 'mkdirs()', 'setReadable()', 'setReadOnly()' and 'setWritable()' work?

> It was also my understanding that file descriptors were representations 
> of opened files.

Maybe those operations don't use file descriptors, but they do use OS filesystem resources.

-- 
Lew

Thread

java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-02 09:35 +0000
  Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-02 07:25 -0800
    Re: java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-02 15:55 +0000
      Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-02 08:17 -0800
        Re: java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-02 16:31 +0000
          Re: java.io.File markspace <-@.> - 2011-12-02 08:53 -0800
          Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-02 14:02 -0800
            Re: java.io.File Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 17:12 -0500
              Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-02 14:16 -0800
                Re: java.io.File Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 18:42 -0500
                Re: java.io.File Lars Enderin <lars.enderin@telia.com> - 2011-12-03 01:06 +0100
                Re: java.io.File Jukka Lahtinen <jtfjdehf@hotmail.com.invalid> - 2011-12-07 15:51 +0200
            Re: java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-05 15:14 +0000
              Re: java.io.File markspace <-@.> - 2011-12-05 07:49 -0800
                Re: java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-05 16:28 +0000
              Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-05 15:25 -0800
                Re: java.io.File Mark <i@dontgetlotsofspamanymore.net> - 2011-12-06 10:29 +0000
          Re: java.io.File Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 17:08 -0500
      Re: java.io.File Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 00:57 -0800
    Re: java.io.File Mayeul <mayeul.marguet@free.fr> - 2011-12-02 17:33 +0100
      Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-02 14:07 -0800
        Re: java.io.File Mayeul <mayeul.marguet@free.fr> - 2011-12-06 15:52 +0100
          Re: java.io.File Lew <lewbloch@gmail.com> - 2011-12-06 09:23 -0800

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