Some of this is part of the framework. JSON continues to be treated as a second-class citizen and static actions can't be unit tested. Some of it is Java: dependency injection sucks, lack of meta programming capabilities, static typing.
It's a lot better than Struts, and if you _had_ to use Java, you'd probably want to use Play. But if you had the choice, what compelling reasons is there to use Play over rails/sinatra/django/web.py/node ?
For me, all of my education on Rails came from online tutorials and books which I have been able to learn the basics from, but not enough to get a job with.
How can students like myself without access to classes on web development really learn the subject? And why would anyone hire a web developer from a school that doesn't teach web development?
Online tutorials, books, and getting practice by doing it seem to be the chief ways that most people learn web development. You could do worse than being able to point to a portfolio of web applications and telling a potential employer "I built these".
Web application development culture tries to be fast, both in terms of developing the initial application as quickly as possible, and rolling changes out to the user as quickly as possible. Having to compile code has traditionally made Java less desirable than Python/Ruby/Perl etc. for the fast cycle of web development.
The Play framework eliminates this problem, but there's cultural momentum built up. After eschewing Java for years due to this, it seems unlikely that Java will quickly recover any warranted popularity amongst web developers.
Java also tends to be more verbose as a language. This can be a good thing in certain settings, but again goes against the desire for fast development.
There is in fact a lot of Java web development going on, but more in situations like developing internal web applications for use within big corporations rather than developing nimble startup code. If you wanted to get a job doing internal web applications for some place like Transamerica or AT&T, Java skills would be good to have.
That said, if you're really into Java/Play, then there might not be a lot of competition to become a leading expert...