Developer spend 75% of their time working on boiler-plate code. Spring Roo do amazing job of doing that for you and gets you started really-2 fast. After that you can follow the application curve if writing the business logic. Why Roo? Define the class and its relation it will generate the DB using hibernate you can generate the controller's ( and UI) from the same classes with CURD operation supported test code is also gets generated code generated is clean and easy to modify dependency resolution happens through maven once you are done projects are eclipse ready easy to get rid of metadata for production Other tools: I came across Grails but i needed a framework which will generate the java so roo was the better choice for me Video helped me get started: http://s3.springsource.com/MRKT/roo/2010-01-Five_Minutes_Roo.mov
My Opinion.