code: @Override
      public BlockLocation[] getFileBlockLocations(FileStatus file, long start,
          long len) throws IOException {
  
        if (file == null) {
          return null;
        }
        String srep = makeAbsolute(file.getPath()).toUri().getPath();
        String[][] hints = kfsImpl.getDataLocation(srep, start, len);
        if (hints == null) {
          return null;
        }
        BlockLocation[] result = new BlockLocation[hints.length];
        long blockSize = getDefaultBlockSize();
        long length = len;
        long blockStart = start;
        for(int i=0; i < result.length; ++i) {
          result[i] = new BlockLocation(null, hints[i], blockStart, 
                                        length < blockSize ? length : blockSize);
          blockStart += blockSize;
          length -= blockSize;
        }
        return result;
      }
docs: Return null if the file doesn't exist; otherwise, get the
  locations of the various chunks of the file file from KFS.