This is right on with what I was thinking, but I'd add that it's the recruiter's job to make the company sound so appealing that new recruits want to work there

This is right on with what I was thinking, but I'd add that it's the recruiter's job to make the company sound so appealing that new recruits want to work there, but they aren't the ones driving work assignments. Not only is it acceptable to ask what you're going to be doing, it's encouraged. They may have well known you'll be doing Java stuff at first, but still flashed the lights in your eyes. Chalk it up to a learning experience.