File locking supported on all platforms?

[Alan Bateman]

On 11/07/2020 15:13, Jonas Konrad wrote:
> I asked around and apparently fcntl locking can be idempotent in the 
> same process at least for some fs, so locking twice in the same jvm 
> may not error even on an fs that does support locks.
You should get an OverlappingFileLockException in that case.  As a 
reminder, the file locking API is intended for coordinating access with 
other programs, it cannot be used to coordinate access to a file in the 
same VM.

I see NFS is mentioned in the discussion. Yes, there can be issues in 
NFS environments but if the lock daemon is not running on the remote NFS 
server then I would expect the lock or tryLock methods to throw an 
IOException "No locks available".

-Alan