code: public void prepare() throws IOException
     {
        if (locks != null)
        {
           bckFiles = new File[files.length];
           for (int i = 0,length = files.length; i < length; i++)
           {
              File file = files[i];
              if (file.exists())
              {
                 String fileName = file.getName().contains(".") ? file.getName().substring(0, file.getName().indexOf("."))
                                                                : file.getName();
                 bckFiles[i] =
                    new File(file.getParent(), fileName + "." + System.currentTimeMillis() + "_" + SEQUENCE.incrementAndGet());
                 move(file, bckFiles[i]);
              }
           }
        }
     }
docs: {@inheritDoc}