public ByteBuffer read(final long off,final int nbytes) throws IOException {
  final ByteBuffer tmp=ByteBuffer.allocate(nbytes);
  FileChannelUtility.readAll(this,tmp,off);
  tmp.flip();
  return tmp;
}

public ByteBuffer read ( final long off , final int nbytes ) throws IOException { final ByteBuffer tmp = ByteBuffer . allocate ( nbytes ) ; FileChannelUtility . readAll ( this , tmp , off ) ; tmp . flip ( ) ; return tmp ; }
read some data out of the file .
