It is "free" if you squint, but they kind of screw with you when you don't pay them, to the point where I ditched jOOQ entirely because I didn't feel like I could trust them to deal straight with me. They spam your application output like nagware unless you dig into the code for an undocumented flag (which has a really godawful guilt-trip comment next to it begging you to allow them to continue littering your logs with unparseable garbage that can't even be bothered to go through logback to be piped correctly) and they hide their unit tests (and are real jerks about them, calling them "an enterprise feature", when in reality they're both documentation and verification that the stuff they say works actually does work). It's their prerogative to do that, of course, but it's not behavior I'd support. Team's kind of shitty on Twitter, too, trolling around keyword searches and looking for a fight.

I don't recommend its use, both from a "can I trust this" perspective as well as a "do I want to support these guys" one. If you can use Slick, I recommend it, as its developers have in my experience been uniformly solid people; I haven't needed either recently, as I've switched stacks for the project I was going to use one or the other for, but Slick's developers don't make me feel icky to support.

And if you sold your soul (I mean infrastructure) to oracle already, jOOQ is the least of your worries!

Also supporting Oracle is a huge PITA. So charging for that is completely understandable :)

Exactly, if you use an Open Source database (e.g. MariaDB or PostgreSQL) you'll be OK with the Open Source version of jOOQ.