code: public static synchronized RenderEngine getInstance() {
      //availableEngines = null;
      if (null == availableEngines) {
        availableEngines = new HashMap();
      }
  
      if (!availableEngines.containsKey(DEFAULT)) {
        RenderEngine engine = new BaseRenderEngine();
        availableEngines.put(engine.getName(), engine);
      }
  
      return (RenderEngine) availableEngines.get(DEFAULT);
    }
docs: Get an instance of a RenderEngine. This is a factory method.
  Defaults to a default RenderEngine. Currently this is a
  basic EngineManager with no additional features that is
  distributed with Radeox.
  
  @return engine default RenderEngine