This is normal, though it's your choice whether it's enough information to bother with an interview.
He's a recruiter. Recruiters often don't share company names because you might approach the company directly, till you've let them submit you to that company so it's "on the record" that they represent you and get their cut.
Also, recruiters don't know the details of day to day tasks of these positions. They know "they want a mid-level Java programmer to program on their financial thingy." Any details they do give you have a 50% chance of being wrong so it's probably for the best.
So you're getting a standard kind of recruiter approach. Based on what you know, maybe that's worth taking time off to interview and maybe it's not. You can just play hardball, and say "Sorry, I don't plan to take off time to interview without more information about the role." They might give you more details, they might have the hiring manager set up a "quick chat" via phone prior to an actual formal interview, or they might move on to someone who's being less high maintenance. If you're OK with any of those outcomes, roll hard.