When locking a file on a NFS4 mounted file system via Java FileLock class under
Linux kernel 3.16.7-24.1 this is not recognized by another Java program on
another OpenSuse computer with kernel 3.16.7-21.1. Going back to kernel
3.16.7-21.1 all is fine.

The NFS4 file system is mounted as
rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=XXX.XXX.XXX.XXX,local_lock=none,addr=XXX.XXX.XXX.XXX
on both machines.

According to
http://stackoverflow.com/questions/23562369/is-a-filelock-a-posix-advisory-fcntl-lock
the Java FileLock class (Sun Java 6) uses POSIX fcntl locks.

The problem is critical because the standard Java Logging implementation is now
broken. The implementation tests if it can exclusively lock the .lck file which
secures a lock file. If the machine with kernel 3.16.7-24.1 created this file
(and locked it) the other machine gets nevertheless an exclusive lock on the
.lck file assuming it created the file and moves the lock file from the first
process away.

Somehow it seems like the local_lock parameter is set to another value than
'none' despite the fact that the mount option was 'none'.