code: public Boolean getConfigValueBoolean(String key, Boolean dflt) {
          try {
              String value = getConfigValue(key);
              return value == null ? dflt : Boolean.parseBoolean(value);
          } catch (Exception e) {
              return dflt;
          }
      }
docs: This is a convenience method for returning a named configuration value that is expected to be
  a Boolean value.
  
  @param key The configuration value's key.
  @param dflt Default value.
  @return Configuration value as a Boolean or default value if not found or not a valid
  Boolean.