It was marketed for a long time to use primarily for Java applets. Moreover, it was marketed as if "old sucking java applets was replaced with javafx", in reality it replaced Swing in applets, not applets. Then, for some period of time, it was marketed as kiosks platform.
I didn't know that it's just a GUI toolkit until recent time when someone told me so. Its website still not says anything sane, what it is. "client application platform for desktop, mobile and embedded systems built on Java". Well, Java itself is application platform for desktop and whatever apps.
No. AIR was a runtime for desktop environments. You could implement standalone applications (and mobile apps) with it. I also worked on a few embedded systems which utilized a user-interface on top of Flash/Flex/AIR.
As far as I can recall it was pretty good, and mostly fun to work with. The framework was quite powerful, and allowed us to write lots of highly interactive code in a short timeframe. At that point of time (maybe 2011?), it was far ahead of anything based on Javascript/HTML, and I think only more recently the more powerful web frameworks might have caught up.
I really enjoyed Flex and look back at it fondly, when I tried Angular 1 it felt like the first thing on the JS/HTML side that could come close to matching the productivity of Flex (albeit with no helpful IDE). It was good enough to whip out a MVP demo in 48 hours. I've mostly been out of UI development since, occasionally extending stuff written in a NIH corporate framework or some Backbone things. Occasional experiments with the ClojureScript tooling (Reagent-based) seem like the next way forward that maybe the rest of the world can use in another 5+ years.
2008~2011 timeline sounds spot on. We had an AIR app, which we started moving to web-based JavaScript around 2011ish I think. It was a lot of custom code; would have been a lot simpler now with something like Angular. And TypeScript would have been alike a chorus of angels.
If I'm not mistaken, JavaFX initially was planned to be a rich-gui-for-everything I think, it was supposed to be used in web applets, desktop and for mobile I think, the ground moved ahead of it way faster tho
That's how it was presented to me. AWT was platform dependent, so you'd get Windows/Mac/Linux-specific inputs like radio buttons when they were created. Swing changed Java's GUI development to be platform independent, making radio buttons appear the same across platforms. With the emergence of mobile devices, and therefore more rendering engines, JavaFX was introduced to to unify design across device (or become device independent).
That said, I suppose JavaFX never took off. I think it wasn't that people hated it, but that the people that would be the primary adopters had already built their applications in Swing or as Applets years/decades ago. JavaFX was an improvement, but convincing a company to change a mission critical GUI would be too costly to do. Coupled with how GUI education in CS is abysmal, everyone stuck with Swing because they didn't want to "learn a new thing they already hated".
