code: public Double getConfigValueDouble(String key, Double dflt) {
          try {
              return Double.parseDouble(getConfigValue(key));
          } catch (Exception e) {
              return dflt;
          }
      }
docs: This is a convenience method for returning a named configuration value that is expected to be
  a double floating point number.
  
  @param key The configuration value's key.
  @param dflt Default value.
  @return Configuration value as a double or default value if not found or not a valid double.