Depending on the project. getting something done faster could be easier with a modern web framwork like Ror or Django (I use Django). But it really depends on what are you trying to build.. Also you should remember that python/ruby enhanced productivity comes with some learning curve, especially for someone coming from java, which is different (not as syntatic but mainly in idioms, best practices etc).

You may want to consider Play framework. another modern web framework that uses scala - which is actually an enhanced and more productive java (and if I recall correctly can compile plain old java as well.. )