I have the "Java Server Programming J2EE Edition" book
(ISBN: 1-861004-65-6).
I downloaded the program from here and I'm trying to run the chat application in chapter 9 but for some reasons it shows me errors like:

C:\ProJavaServer\Chapter09\chat\src>javac ListRoomsServlet.java
ListRoomsServlet.java:5: package javax.servlet does not exist
import javax.servlet.ServletException;
                     ...
or
C:\ProJavaServer\Chapter09\chat\src>javac ChatRoomServlet.java
ChatRoomServlet.java:6: package javax.servlet does not exist
import javax.servlet.ServletException;
                     ...
and other more...

Please help me with this problem.
Thank you.