code: private void applyDefaults() {
          for (String name : getOptionNames()) {
          	String val = _map.get(name);
          	if (val == null || val.length() == 0) {
                  OptionDefinition opt = OptionDefinition.get(name, this);
                  _map.put(name, opt.getDefaultValue());
              }
          }
      }
docs: Apply defaults to the options, where possible.