code: public static String formatSize(final long value) {
          double size = value;
          DecimalFormat df = new DecimalFormat("#.##");
          if (size >= GB) {
              return df.format(size / GB) + " GB";
          }
          if (size >= MB) {
              return df.format(size / MB) + " MB";
          }
          if (size >= KB) {
              return df.format(size / KB) + " KB";
          }
          return String.valueOf((int) size) + " bytes";
      }
docs: Returns formatted size of a file size.
  
  @param value
  The value
  @return String