code: private JsonToken readLiteral() throws IOException {
          value = nextLiteral(true);
          if (valueLength == 0) {
              throw syntaxError("Expected literal value");
          }
          token = decodeLiteral();
          if (token == JsonToken.STRING) {
              checkLenient();
          }
          return token;
      }
docs: Reads a null, boolean, numeric or unquoted string literal value.