private static VirtualFile @Nullable [] filterFilesWithContent(@Nullable VirtualFile @Nullable [] files) {
    if (files == null) return null;

    return ContainerUtil.filter(files, FILE_WITH_CONTENT).toArray(VirtualFile.EMPTY_ARRAY);
  }
private static VirtualFile @Nullable [] filterFilesWithContent(@Nullable VirtualFile @Nullable [] files)