code: public void configure(String filename, boolean isExternalFile) {
          try {
              Properties properties;
              InputStream inputStream;
  
              if (!isExternalFile) {
                  Resources resources = context.getResources();
                  AssetManager assetManager = resources.getAssets();
  
                  inputStream = assetManager.open(filename);
              } else {
                  inputStream = new FileInputStream(filename);
              }
  
              properties = loadProperties(inputStream);
              inputStream.close();
  
              startConfiguration(properties);
          } catch (IOException e) {
              Log.e(TAG, "Failed to open file. " + filename + " " + e);
          }
      }
docs: Configure using the specified filename.
  
  @param filename       the filename of the properties file used for configuration.
  @param isExternalFile the filename is from assets or external storage.