12.
Which of the following is true about servlet containers (e.g., Tomcat)?

13.
What does the term "URL mapping" refer to in Java Servlets?

17.
In Java Servlets, what is the purpose of the `doFilter()` method in the `Filter` interface?

18.
What is the purpose of the `context-param` element in the `web.xml` file of a Java web application?