code: private double getParamDouble(String key, double defaultValue) {
          String value = values.get(key);
          if (value==null || value.isEmpty()) {
              return defaultValue;
          }
          try {
              return Double.valueOf(value);
          } catch (NumberFormatException e) {
              throw new RuntimeException("Invalid double value: >>>"+value+"<<<", e);
          }
      }
docs: Returns the double, or the default is absent. Throws if the double is specified but invalid.