[zred]

A very interesting look at Play can be found in this presentation: http://spinscale.github.com/play-advanced-concepts.html

The author wrote the Play Framework Cookbook and so it's a presentation from someone that can be considered a bit of an authority on Play (and not someone with an axe to grind). However, the presentation covers a bit of what worries me about Play. Play rewrites the bytecode for things like emulating properties and allowing you to pass whatever you want to the templates and have it automatically name the variables based on their local names in the calling method.

For me, the reason to use Java over Python or Ruby would be to move away from some of the behavior used in those languages that can make debugging and static analysis harder.

I've used Play for some hobby stuff (and kept up on Play 2.0). Play 2.0 seems to remove the former system for passing variables to the templates in favor of a system where templates accept certain parameters with types (a welcome change for me). However, at least the last time I played with it, Eclipse couldn't tell me what variables and types the template was expecting.

I guess Play leaves me feeling like it brings the magic to me without as much ease that Python and Ruby offer (or, at least, without as much familiarity). That might be changing - I think that the changes in the templating for 2.0 show a clear move in that direction. I really wish them well since it's always good to have more good options for development and there's a lot of Java already out there to leverage.