Sure, though they generally achieve that by running on big iron, with lots of spare CPU and memory, and running a lot of big exotic software. That is, environments with the opposite of where you'd generally want to deploy any code bare metal.
The Aonix data on their website was very useful. It proved most of our points. That's why we reference it. Still available through archive.org. Although, just checking, I find a lot of the good links are dead on the times I tried. Uh oh.
In the Aonix design, there is no GC on the hard-real-time threads or portions of the heap. Those are usually done statically anyway for max predictability. The GC can apply to anything else with it preempted by real-time threads when necessary. It was usually tied into a RTOS like LynuxWork's (now Lynx).
I still refer to Aonix, because they were more developer friendly, had more information on their website than the few whitepapers from PTC and the web site is still partially up.
There are a number of commercial real time JVM's out there.