docs: public static void storeCache(Map<String, String> map, File file) {
          BufferedWriter bw = null;
          try {
              // Ensure that we the directory exists (maybe this should be done at
              // another place).
              file.getParentFile().mkdirs();
              bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file)));
              for (Entry<String, String> en : map.entrySet()) {
                  bw.write(en.getValue());
                  bw.write(' ');
                  bw.write(en.getKey());
                  bw.write('\n');
              }
          } catch (IOException e) {
              e.printStackTrace();
          } finally {
              FileUtil.closeAndIgnoreExceptions(bw);
          }
      }