docs: public static void loadCache(Map<String, String> cache, File file, int maxSize) {
          BufferedReader br = null;
          try {
              br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
              String line = null;
              while ((line = br.readLine()) != null) {
                  int sepIndex = line.indexOf(" ");
                  String hash = line.substring(0, sepIndex);
                  String urlExternalForm = line.substring(sepIndex + 1);
                  cache.put(urlExternalForm, hash);
              }
          } catch (FileNotFoundException e) {
              // Nothing: New cache will be used.
          } catch (IOException e) {
              e.printStackTrace();
          } finally {
              FileUtil.closeAndIgnoreExceptions(br);
          }
      }