Is there any Java web2.0 Tag opensource project?

I want to start a web project开发者_StackOverflow中文版 relating to Java Web 2.0, I hope to find something helpful. Do you have any suggestions?

---

Here is a resource for open source web 2.0 frameworks in Java:

http://java.adgoogy.com/open-source/web-20

Hopefully one of those can get you started on the type of project you want to create.