Inferred type ‘S’ for type parameter ‘S’ is not within its bound; should extend …

springboot 2下：

    @Override
    public Editor findOne(int id) {
        return repository.findOne(id);
    }

报错：

Inferred type 'S' for type parameter 'S' is not within its bound; should extend 'com.test.markdown.domain.Editor'

解决方法：
将repository.findOne(id); 改为
repository.findById(id).orElse(null); 或 repository.findById(id).get();