Eclipse:the superclass Javax.servlet.http.HttpServlet is not found on the Java Build Path

When we were using Eclipse for Java web development, there might be an error: The superclass Javax.servlet.http.HttpServlet was not found on the Java Build Path. How do we solve this problem?

2. The errors we encountered appear as follows:

4. We right-click the folder with the error prompt, as follows:
6. We click on "Configure Build Path", as follows:
8. We then click on "Add Library", as follows:
10. We select the winning option, then click Next, as follows:
12. We then click "Done", as follows:
14. We can then click "Normal" to complete the setup. So my mistake will disappear, as follows:

Eclipse:the superclass Javax.servlet.http.HttpServlet is not found on the Java Build Path