I wrote a java application that accesses a file while other Processes in other VMs try to do the same. Therefore I use the FileLock class:
FileOutputStream fos = new FileOutputStream(filePath,append);
FileChannel f = fos.getChannel();
FileLock lock;
while ((lock = f.tryLock()) == null){
try {
Thread.sleep(100);
} catch (InterruptedException ex) {
Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
}
}
OutputStreamWriter out = new OutputStreamWriter( new FileOutputStream(filePath,append));
out.write(textToWrite);
out.close();
lock.release();
All works fine on Mac OSX, but when I run the code on Windows 7 it throws an IOException at the line
out.close();
, when trying to flush.
java.io.IOException: The process cannot access the file because another process has locked a portion of the file
at java.io.FileOutputStream.writeBytes(Native Method)
As far as I understand from How does FileLock work?, the actual obtaining of the lock with
f.tryLock()
forbids me to access it since another process (this one apparently) has exclusive lock.
Now that strikes me as a paradoxon - how am I to obtain an exlusive lock to enable me to write to the file without danger of other processes messing with it at the same time when the actual act of obtaining the lock hinders me to do so?
And consequently why does it work on Mac OS and not on windows? I know from the JavaDocs that there are OS specific differences and difficulties with the FileLock class, but surely not with respect to its designed-for functionality. Since this can't be the case, I am doing something wrong and this is where I ask for your help.
Thx, M
