code: public static void substituteDeprecatedConfigKey(Configuration config, String deprecated, String designated) {
  		// set the designated key only if it is not set already
  		if (!config.containsKey(designated)) {
  			final String valueForDeprecated = config.getString(deprecated, null);
  			if (valueForDeprecated != null) {
  				config.setString(designated, valueForDeprecated);
  			}
  		}
  	}
docs: Sets the value of a new config key to the value of a deprecated config key.
  @param config Config to write
  @param deprecated The old config key
  @param designated The new config key