code: private static FacesInitializer _getDefaultFacesInitializer(ServletContext context)
      {
          // No MyfacesConfig available yet, we must read the parameter directly:
          String initParameter = context.getInitParameter(MyfacesConfig.INIT_PARAM_SUPPORT_JSP_AND_FACES_EL);
          if (Boolean.FALSE.toString().equals(initParameter))
          {
              return new FaceletsInitilializer();
          } 
          else if (ContainerUtils.isJsp21(context)) 
          {
              return new Jsp21FacesInitializer();
          } 
          else 
          {
              return new Jsp20FacesInitializer();
          }
      }
docs: Returns a FacesInitializer that fits for the current environment (JSP 2.0 or 2.1).
  @param context
  @return