There are many good frameworks out there, but the one I prefer for quick demos, simple applications and rapid scaffolding is Grails. Why? Simply put – with just a few lines of code you have a fully functional application: user interface, controllers, data validation and persistence.
But Grails is much more than a tool for quick prototypes. It is a fully featured platform based on the rock solid foundation of Spring, Hibernate and other enterprise-grade frameworks. Plug-ins can be added any time and they will seamlessly add new features to the application.
Grails uses Groovy as its primary programming language, but as it runs on the Java Virtual Machine, you have full access and interoperatbility with any existing Java library. Tooling support is also excellent, both from command line and from IDEs like Eclipse or IntelliJ IDEA.
If you think that the above paragraphs are just hyperboles from an enthusiast fanboy, continue reading and experiment for yourself how easy is to build a new app from scratch.