docs: private String readFileIntoString(String fileName,  InputStream is) throws IOException {
          FileInputStream stream = null;
          InputStreamReader reader = null;
          try {
              if (is != null) {
                  reader = new InputStreamReader(is, charset);
              } else {
                  stream = new FileInputStream(fileName);
                  reader = new InputStreamReader(stream, charset);
              }
              
              return readStreamIntoString(reader);
          } finally {
              if (reader != null) {
                  reader.close();
              }
              if (stream != null) {
                  stream.close();
              }
          }
      }