@NotNull
  @Override
  public FileBasedIndex.InputFilter getInputFilter() {
    return new DefaultFileTypeSpecificInputFilter(JavaFileType.INSTANCE) {
      @Override
      public boolean acceptInput(@NotNull VirtualFile file) {
        return super.acceptInput(file) && JavaFileElementType.isInSourceContent(file);
      }
    };
  }
@NotNull
  @Override
  public FileBasedIndex.InputFilter getInputFilter()