File locking supported on all platforms?

[Stefan Reich]

Hi Jonas,

what would happen if I try to lock a file on these platforms? Can I
reliably detect this case? That would already help a lot.

The use case is ensuring a database's consistency which I now do over a
socket protocol, but file locks would be faster and more reliable.

Stefan

On Sat, 11 Jul 2020 at 11:45, Jonas Konrad <me at yawk.at> wrote:

> Hey,
>
> Some file systems on Linux, eg old NFS, do not support locking at all.
>
> - Jonas
>
> On 7/11/20 11:36 AM, Stefan Reich wrote:
> > Hi,
> >
> > a quick question regarding file locks in Java. I seem to remember
> > reading somewhere that this feature isn't guaranteed to work on all
> > platforms. However, I can now find no mention of that e.g. here
> > <
> https://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileLock.html
> >.
> >
> > The page does list that numerous special assumptions may fail, for
> > example that programs which /don't/ lock a file are prevented from
> > changing it when it is locked by another program.
> >
> > However, I only care about the basic feature, namely that one local file
> > cannot be locked by two Java programs at once and will cause one of them
> > to throw an exception.
> >
> > Is this guaranteed to work everywhere?
> >
> > Many greetings
> > Stefan
> >
> > --
> > Stefan Reich
> > BotCompany.de // Java-based operating systems
>


-- 
Stefan Reich
BotCompany.de // Java-based operating systems
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