Synchronous write to same file using different file pointers

[Alexander Duenisch]

Hi ranchers,

i have written a piece of code like the following:

public void writeStuff(byte[] stuff, long location) 
throws IOException {
 
  RandomAccessFile raf = new RandomAccessFile("file.txt", "rw");
  try {
    raf.seek(location);
    raf.write(stuff);
  } finally {
    raf.close();
  }
}

This function is being called by multiple threads.
Let's assume it can be guaranteed by the choice of value for location
and the length of array 'stuff', that one thread doesn't
overwrite the bytes written by another thread.

Because the RandomAccessFile is local to the method,
each thread would create it's own instance and use the associated
file pointer.

Can this be done safely or do i have to put the call to write in a
synchronized block?
In other words:
Can two or mor threads write synchronously to different locations of
the same file using different RandomAccessFile objects and thus
different file pointers, if there is no risk of one thread overwriting
another's data?

Thanks in advance for your answers.

Alex D.

[Ulf Dittmer]

I would have assumed that it's not even possible to have two file handles that perform simultaneous write operations, but I'm no expert on file systems.