Make Swagger UI usable even with class inheritance on Spring Boot

Since the front end and back end developers can be normally working in different teams, the documentation of the API provided by the back end becomes more and more important for communication and integration.

For the back ends which are built by Spring Boot, the Swagger which is implemented by Springfox is the most popular way to provide the API documentation, because it not only renders a UI but also provides an API documentation in JSON format for code generation on client side.