Your classpath does not include the correct library. You need a servlet library
in your classpath. You can find a link to the servlet library at
http://sun.java.com/products/servlet.

Dominic Guan wrote:
> 
> javac WebMail.java
> WebMail.java:4: cannot resolve symbol
> symbol  : class HttpServlet
> location: class WebMail
> public class WebMail extends HttpServlet {
>                              ^
> WebMail.java:6: cannot resolve symbol
> symbol  : class HttpServletRequest
> location: class WebMail
>    public void doGet(HttpServletRequest request
>                      ^
> WebMail.java:6: cannot resolve symbol
> symbol  : class HttpServletResponse
> location: class WebMail
>    public void doGet(HttpServletRequest request
> WebMail.java:7: cannot resolve symbol
> symbol  : class ServletException
> location: class WebMail
>       throws ServletException, IOException {