Head First tries to encourage you to start developing applications directly using tomcat instead of Eclipse or any other IDE. The reason is the same as with the SCJP - sometimes the IDE does something for you without even bothering telling you about it. It might be frustrating for the newcomers, as well as when you need to type something by yourself you're remembering it better.
I doubt the warning shown by you is the reason of your problem.
Could you please prepare the structure of your web application (you know - main directory, WEB-INF directory, web.xml in it etc.) along with your files in the directories and show it to us?
After this, we can together try -- step by step -- solve your problem :-)
Ok Sumit, so:
- is your web.xml file called web.xml or with capitalized W like on your diagram (Web.xml)?
- What is the result of starting the server with so defined application? 404 Error, cannot load page, ...?
You can try to prepare this application all by yourself (which is preferred for SCWCD candidates), by creating a simplified web application structure:
Now put the code you posted into the index.jsp and web.xml files (or just copy the ones you already have).
I guess you have a Apache Tomcat installed already (what version?) if so, than copy this whole HelloWorld directory (application) into the TOMCAT_HOME/webapps/ directory and execute TOMCAT_HOME/bin/startup.sh.
You can also take a look at tomcat logs at TOMCAT_HOME/logs/catalina.out if it shows something gone wrong. After this - try opening:
http://localhost:8080/HelloWorld in your browser and tell us what you'll see.
PS. You need to be sure that no other Tomcat instance is running on the specified port. You can do that using netstat command if you're on Linux or i.e. windows system manager to see what processes are currently running. You can also test it by going to http://localhost:8080 and seeing if it will show 'cannot establish connection' type of error (Tomcat is off) or 404 Tomcat-style layout (tomcat is on).
PS2. You can use the "code" tag for the code you show, as it will increase the readability of your post