web-application-design

I'm starting a new Java web app from scratch. I don't have much experience on Spring Framework, but I know I'd like to use some of its features, such as Transaccions Management. On the other hand, I really like Guice for dependency injection. I know that Guice and Spring can work together: http://www.jroller.com/mindcrime/entry/an_example_of_integrating_guice But before starting designing my application, I wanted to know if someone had experienced issues by following that approach. Also, what I really like from Guice is that you don't need an XML configuration file, but just java Modules,

I am relatively new to php. There is a very basic thing that has been troubling me. I understand that php is used to make web sites dynamic. I also understand that php is one of the many server side scripting languages that can be used to make dynamic web sites. However, what I do not understand is that when do i need to use an index.php page. Say for example if i have just a simple login page on my index page, it could very well just be a simple html page as well. Right? Then why would i want to make it index.php instead of index.html? An example of a sample situation would be great. You will