public static boolean isLibraryRoot(@NotNull VirtualFile directoryFile, @NotNull Project project) {
    final ProjectFileIndex projectFileIndex = ProjectRootManager.getInstance(project).getFileIndex();
    if (projectFileIndex.isInLibraryClasses(directoryFile)) {
      final VirtualFile parent = directoryFile.getParent();
      return parent == null || !projectFileIndex.isInLibraryClasses(parent);
    }
    return false;
  }
public static boolean isLibraryRoot(@NotNull VirtualFile directoryFile, @NotNull Project project)