@Override
    public void saveExtension(@NotNull JpsProject project, @NotNull Element componentTag) {
      JpsJavaProjectExtension extension = getService().getProjectExtension(project);
      if (extension == null) return;

      String outputUrl = extension.getOutputUrl();
      if (outputUrl != null) {
        componentTag.addContent(new Element(OUTPUT_TAG).setAttribute(URL_ATTRIBUTE, outputUrl));
      }
      LanguageLevel level = extension.getLanguageLevel();
      componentTag.setAttribute(LANGUAGE_LEVEL_ATTRIBUTE, level.name());
      componentTag.setAttribute(
          "assert-keyword", Boolean.toString(level.compareTo(LanguageLevel.JDK_1_4) >= 0));
      componentTag.setAttribute(
          "jdk-15", Boolean.toString(level.compareTo(LanguageLevel.JDK_1_5) >= 0));
    }