It is necessary to define each servlet that Tomcat will use.  This is done in a file called "web.xml."  Also, the compiled servlet class must be placed in a specific location.

Open Windows Explorer.
Locate the folder named "cis237" that you created in the "Configuring Tomcat" lecture of Module 8.
Create a new folder inside "cis237" named "WEB-INF".  Pay close attention to capitalization.
Create a new folder inside "WEB-INF" named "classes"

Your compiled servlet class must go in the "classes" folder.

Next, you need file named "web.xml".  Download this one and put it in the "WEB-INF" folder.

Open the file in a text editor, and replace "CIS237Servlet" with the actual name of your servlet class.

The purpose of this file is to define the environment of your web application.

The  tag provides a logical to physical mapping.  It allows us to provide a name for the servlet that will be typed into the Address/Location bar.  That name is mapped to a specific class file.