private static void onJavaFileReferencesBuilt(@NotNull RefFile refFile, UFile file) {
      RefModule refModule = refFile.getModule();
      if (refModule != null && LanguageLevelUtil.getEffectiveLanguageLevel(refModule.getModule()).isAtLeast(LanguageLevel.JDK_1_9)) {
        Set<String> packageNames = getImportedPackages(refModule);
        if (packageNames != DONT_COLLECT_PACKAGES) {
          Stream.concat(file.getImports().stream().map(st -> getPackageName(st)), 
                        file.getImplicitImports().stream())
            .filter(p -> !StringUtil.isEmpty(p))
            .forEach(packageNames::add);
        }
      }
    }
private static void onJavaFileReferencesBuilt(@NotNull RefFile refFile, UFile file)