Good open source web app using Servlets/JSP?

Question

I'm wondering if anyone knows of a good quality open source web application that uses Servlets/JSP. Reason for this is that I'm currently maintaining a web application and it doesn't look like it was designed properly. I'm a junior developer so I don't have a lot of experience with this and I don't have a mentor to teach me. Some bad design choices (I think) are:

• All controllers must extend a class called Controller which forces you to override both doGet and doPost
• A singleton database class that connects to a database using JNDI. Compiler warns me that this is deprecated.
• Messy error pages. From what I've read, I could set all the error pages using the DD.
• A Model class that extends HashMap and it's using completely raw types (ugh!)

Answer 1

There's an Oracle page with Java EE tutorials on it for versions 3 through 6.

Those tutorials will have good sections on Servlets/JSP in them that can be referenced and used.

There's a lot of information there but the individual sections are helpful too (have personally consulted individual sections many times and have found it very helpful).