Spring Framework - The Spring Framework provides a comprehensive programming and configuration model for modern Java-based enterprise applications - on any kind of deployment platform.
Apache Struts - Apache Struts is an open-source web application framework for developing Java EE web applications.
Grails - An Open Source, full stack, web application framework for the JVM
Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
Apache Jena - Java Web Frameworks
Eclipse RAP - Java Web Frameworks