Tapestry is hands-down the worst framework I've ever used. It destroys your ability to reason about your code, because what you write looks like java but no longer follows java semantics (Want to initialize your page objects? You can't, you're expected to null-check your fields and reinitialize them every time you want to access them. Want to pass a parameter into a page you're linking to? Put an annotated field in your page that's typed to the other page, and call a magically-named method on it. I wish I was making this up). And it forces you to spread your flow logic between your pages and your templates; standard practice for repeater components is to have the logic for displaying the repeated component read the data it needs from a field on the outer component object, which is populated by the loop in the template. To get any sense of where data is coming from you have to flick back and forth between two files (actually usually more like six, because when you have multiple components on a page they're not isolated from each other in any way).

If you want a good web framework for Java, try Wicket. Components are real objects written in standard java, and proper separation between logic and presentation is enforced (because wicket markup files can't contain any logic).