I would use Java for GWT, if nothing else. Being able to write a huge and complex application for the web, using Java both for the client and server code is something I would not want to live without (links in my profile for examples).
But besides that, Java is extremely mature, has great tooling, huge community and of course an enormous ecosystem with all the third party tools and libraries that come with it. The language is a bit primitive (but improving with each release), and the 'enterprise consultant' mindset of complexity for its own sake can be a turn-off, but overall, yeah, I like using Java.
But besides that, Java is extremely mature, has great tooling, huge community and of course an enormous ecosystem with all the third party tools and libraries that come with it. The language is a bit primitive (but improving with each release), and the 'enterprise consultant' mindset of complexity for its own sake can be a turn-off, but overall, yeah, I like using Java.