What is Tapestry 5 ?
Pure Java and Polyglot
Written in pure Java: code your pages and components in Java, Groovy or Scala.
Convention Over Configuration
Say goodbye to endless XML configuration files: dependency injection and meta-programming through annotations and naming conventions.
Live class reloading means that the time between seeing an error and providing the fix is seconds, not minutes.
Scales up big on a single server, and works great in a cluster. Keeps session state minimal by design.
Advanced Exception Reporting
Gives you all the tools you need to fix your problem: not just a stack trace, but every bit of information you need to know about what Tapestry was doing, why it was doing it, what went wrong, and how to fix it.