Why servlet-name tag is there?

[Pranav Pal]

Why cannot

  <servlet>
    <servlet-name>HelloServlet</servlet-name>
    <servlet-class>HelloServlet</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>HelloServlet</servlet-name>
    <url-pattern>/HelloServlet</url-pattern>
  </servlet-mapping>

be replaced by

  <servlet>
     <servlet-class>HelloServlet</servlet-class>
     <url-pattern>/HelloServlet</url-pattern>
  </servlet-mapping>

Why is the need of <servlet-name> tag?

[Ben Souther]

The first one declares your servlet.

The second one creates a mapping for your servlet.
You can have multiple mappings that point to the same servlet.
You can also declare a servlet with a jsp-file instead of a servlet class.
You can also have multiple servlet entries with the same servlet class (and different configurations).

All of this would be hard to express in a singe tag.