<p>I've been arguing with some friends on the university, and we can't get to a point to which is the framework with more scalability for web applications (and still very fast).</p>

<p>One calls for jsp, the other one for ruby other for php and so on. Could i ask you to clarify us on what as more scalability potential?</p>

<p>Tks, hope I'm not duplicating anything I've searched but didn't found any previous question like this.</p>

<p>Edit: If you could point a comparison about this it would be good :)</p>

Algorithms will count more for scalability than the language used.
That said, there will be differences in execution speed between the languages. I believe that Java (Servlets and JSPs compile to servlets, i.e., native code) will be faster than Ruby and PHP by some amount). There are also a tonne of web frameworks for Java that will encourage you to do things the best way for scalability.
Also design your app so that it can run happily behind a load balancer, and scalability becomes a lot easier :) This isn't my field of expertise however.