Why GWT?
GWT is a set of tools which allows you to write javascript code in java language. That is, to avoid confusion, GWT does not have a lot in common with tons of existing Java technology stacks out there.
It is designed in a such way that backing your javascript application by server build on top of Java stack becomes a huge advantage. However, it does not mean that you can’t build GWT apps backed by PHP/Python/Ruby servers which might be more lightweight solution (both from technology & business points of view).
