RFR: 6244047: impossible to specify directories to logging FileHandler unless they exist

Jason Mehrens jason_mehrens at hotmail.com
Tue Nov 13 20:36:08 UTC 2012

Looking at the webrev again I think I tricked myself into thinking that 'parentFile' was a file that could be opened with a stream when it actually is a directory.  I think the best fix would be to add a check in the catch block (around line 432) and only continue if the directory of the generated file java.nio.file.Files.isWritable/isDirectory otherwise throw the original exception.
If the running JVM terminates abnormally won't the lock file fail to be deleted?  On restart, the lock file will exist to protect a dead process.

Date: Tue, 13 Nov 2012 13:25:27 -0500
From: jim.gish at oracle.com
To: Alan.Bateman at oracle.com
CC: jason_mehrens at hotmail.com; core-libs-dev at openjdk.java.net
Subject: Re: RFR: 6244047: impossible to specify directories to logging FileHandler unless they exist

On 11/13/2012 07:08 AM, Alan Bateman wrote:

On 12/11/2012 23:22, Jim Gish wrote: 
Which file(s) are you concerned about truncating/damaging?  The code I'm impacting is for creating a new lock file.  Where is the potential for truncating/damaging that you both are referring to?

Is this sufficient (plus the proper exception handling of course) ?

                    //lockStream = new FileOutputStream(lockFileName);
                    fc = FileChannel.open(new File(lockFileName).toPath(), CREATE_NEW, WRITE);
                    //fc = lockStream.getChannel();
CREATE rather than CREATE_NEW so that it doesn't fail if the lock file already exists. Although it's just a lock file then I think it would be impolite to truncate it.

You could use Paths.get(lockFileName)rather than new File(lockFileName).toPath() here but either is fine.

I think we want it to fail if the lock file already exists.  That's why I used CREATE_NEW.  At least the way the logic is now, is that it attempts to create a new file and if it fails it tries again until it can create a new one.  It may be the case that the lockFileName is not in the locks map, and thus we don't own it, but it's possible that another JVM/app is logging in the same location.  It, of course, would be bad practice, but not disallowed.  We shouldn't be grabbing a lock file that might otherwise be in use.

Jim Gish | Consulting Member of Technical Staff | +1.781.442.0304
Oracle Java Platform Group | Core Libraries Team
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