Are Java apps Determined or Free-willed?

I keep reading how Java applications are indeterminate. I can see how a multi-threaded application running on a time-sliced thread scheduler would be indeterminate. I also see how the look of a Layout manager would vary from platform to platform. But surely an application running on a specific platform that uses a pre-emptive thread scheduler would be as determinate as an application on that platform written in C++. Am I totally out to lunch on this one?
Dan

In the usual Java environment, you don't have tight control over when garbage collection occurs or how long it takes. If it doesn't happen often, perhaps because you gave the applications lots of memory, it may take a long time when it does occur. I imagine that how this is handled changes somewhat with each major JVM release.
Pre-emptive scheduling, whether by the OS or by the virtual machine, is implementation-dependent for most systems, except maybe for some systems designed for real-time operation.

Okay, thanks.
I forgot about the independent nature of Garbage collection, and didn't realize that Pre-emptive scheduling varied according to the JVM.
Dan