I'm creating a prototype for a java web application. Frontend is a Swing-based java applet. Backend should be a type of web-service, that is called by applet. Backend should run inside a servlet container and should have its own security (username/password) database. I know, that Tomcat has its own user database (realm), but the app should have own. Web-services, in turn, carrying out app logic and database access (via Hibernate). I'm a newbie for a web development and I'm getting lost in a huge amount of the java web frameworks. Even just reading 'introduction' and 'getting started' documents takes a lot of time. So I need an advice which framework(s) are suitable for the task and not very complex for a quick start.

Thank you