Here's a video of James Gosling showing the the Star7 PDA: https://www.youtube.com/watch?v=Ahg8OBYixL0 It's absolutely mindblowing what they built in one year in 1992(!). It had had a touch screen and inertial scrolling.
Wouldn't that be prior art to Apple's scrolling patent?
Invalidating prior art? Well, that's a very different question.