If you want the user to choose the feature type to load, you can programmatically show the Lucy selection UI. This is the dialog box that also appears when a Lucy user drags-and-drops a server URL on the map. 

public void connectToWFSServer(ILcyLucyEnv aLucyEnv, ILcyGenericMapComponent<?, ?> aMapComponent) throws IOException {
  String serverName = "https://sampleservices.luciad.com/wfs";

  //Present the WFS UI to the user
  //This is the equivalent of drag-and-dropping the URL on the map.
  //Note that this should be called on a background thread to avoid blocking the UI
  TLcyDataFormatManager dataFormatManager = aLucyEnv.getDataFormatManager();
  dataFormatManager.handleDataSources(new String[]{serverName},
                                      aMapComponent,
                                      null,
                                      aMapComponent.getComponent());
}