This has nothing to do with Netbeans (except that overreliance on it caused you to lack understanding of what you're doing).
You should read a basic tutorial on how to create and configure web applications in Java, especially Servlets.
That should open your eyes to the small but deadly oversight (or rather 2 of them) you appear to have been guilty of here.
1) don't use the default package.
2) where's your web.xml entries for that servlet (do you even have a web.xml?).