@Override
  public VirtualFile @NotNull [] getContentRoots() {
    Collection<ContentEntry> content = getContent();
    List<VirtualFile> result = new ArrayList<>(content.size());
    for (ContentEntry contentEntry : content) {
      final VirtualFile file = contentEntry.getFile();
      if (file != null) {
        result.add(file);
      }
    }
    return VfsUtilCore.toVirtualFileArray(result);
  }
@Override
  public VirtualFile @NotNull [] getContentRoots()