Ruby on Rails or the beauty of instant feedback

I was trying to write a GWT application that would help track the weight , calories and training for a person and make it run in the Google App Engine. Unfortunately I was always blocked by some configuration issues which made me delay it (being tired after work does not help).
So Saturday I thought maybe I should give this Ruby On Rails a try since I am into ruby a lot lately.
Using Netbeans I started with the sample "Depot application" and started to understand RoR a week ago.
After watching this video of DHH presenting Ruby on Rails and the concept of scaffolding I was able to get started in no time .
Today (less than 24 h since I started) I have a working weight tracking application which needs some improvements .. but it is working.
Being able to avoid the compile/deploy/test cycle and replacing it with just "test" was a huge benefit for me.
Instant feedback is really enlightening and reminds me of the reasons I actually loved PHP years ago. As a beginner programmer I wrote "working" PHP code that was horrible with no MVC separation .. or layering. It was a shame but it worked.
Right now when looking at Rails I see somehow what PHP should have been like ages ago .. the benefits of PHP and the engineering I used to see only in J2EE frameworks. And best of all I did not have to write one SQL line .. this is fantastic for me :).

Yes I know a Jedi JEE programmer must be able to just figure out things such that a single deploy will be enough for all fixes. Well it usually ain't the case and I find myself waiting for the machine to deploy only to find other things to fix .. which I thought were fixed and the human brain can only keep track of 7 things at a time .. add to this the typical open plan office space , personal concerns or other thoughts and you get minimal productivity ..
I realize running the projects inside Netbeans and/or Eclipse allows sometimes the automatic redeployment but even that takes time.
We have MVC , Active Record pattern for ORM , automatically generated unit-tests, integration-tests, functional tests , the famous convention over configuration rule , clean layers (except the service layer that for now I do not miss).
As I read in Bruce Eckel's "Thinking in Python" (for a while I wanted to choose between Ruby and Python) it's not the static type checking or compiling that brings so many benefits it's the use of unit-tests.
Hence I strongly believe well written Ruby on Rails applications can be equal or equivalent to J2EE applications for the same purpose it the test driven development technique is used. Moreover I wrote way too much Java to know that not using unit tests and a technology like EJB2.0 can lead to almost 0 productivity (unit tests seem to help as you do not have to start the container just for a small function you just wrote).
Yes the same can be said about PHP .. you can write horrible code in any language , but Ruby is the new high level language of the day and I tend to go with the flow.
Of course being an Java developer /architect wanna be I realize my 10 years experience in Java are going down the drain with this Ruby on Rails stuff but if I can get things done while having fun .. why not ?
Of course if I have to develop something that has to be distributed and integrate with other tools I will still go for Java but some smart guy invented JRuby meaning I could be running Ruby in a JEE container in order to do a slow migration.
Of course making a JEE application go through the build deploy cycle without issues would be nice , I just can't see how.
This link shows how much time we are loosing with deployment and 2.5 weeks a year looks like a lot considering just the salary of the average developer.