Yeah it sounds interesting, particularly for developers who like to diversify.
Although the large percent of my career has been developing content management and "corporate" applications in PHP, wether i had to or not, now i mostly been focusing on Python/Django because i like the language, the tooling and feel productive in it, on the things i have to do.
But always loved Java, even when i was learning PHP 11 years ago, i spent a lot of time around Struts (1.x), Hibernate and Ibatis, that's where i got the MVC/ORM/Framework skills from, which was useful for "easily" picking/understanding a lot of other stuff in other languages. Also when Groovy got some traction, i spent personal time fiddling with it, was cool, which also lead to spending some time around Grails. But i never got deep in pure Java skills, even though i have a 700 page "bible" around the house somewhere.
Also tried out Jboss Seam, which found out to be kind of awesome for somethings and at a time was contracted for 4 months, to extend features on an existing project built on it, although grasping the whole JSF/J2EE life-cycle can be a pain and still ended the project missing a lot of know-how about it all. For another particular short-time job, i developed some EJB "if it's not working, there's not enough XML in it" 2.1 code.
Not being a rocket engineer (not even an engineer) and a perfectionist trying to meet deadlines, i ended up loving Python and Django, good ORM, good tooling, community and the backend admin feature is a killer one for me.