Does ExecuterService handle threads on multiple cores?

Question

Java

Hello! I'm new to Java, I'm currently reading a book and a question arose about multithreading:
The book says that different threads can run on different cores. As I understand it, everything that concerns, so to speak, the old thread model (Thread / ExecuterService) is always performed on the same core, and the new Fork / Join Framework API just allows you to separate threads by cores.
Is it so? Or can ordinary Threads also run on different cores?

Answer 1

see https://youtu.be/W82D9eUn6q8?list=LLmQvzzT2ZgTt1MZ...
perhaps it is difficult for a beginner, but interesting.
Regarding your question:
there were different approaches to building parallel computing (with different classes)
, they all gave approximately the same results (almost all)))
the result is that on an n-core processor, the calculation speed grows with the number of computation threads up to the number n. then stops.
This says that all implementations (thread classes, executors, etc.) use a lot of coreness. By the way, you can repeat these experiments yourself. It's pretty easy.
Of course it depends on the virtual machine (jvm), but I think almost all of them use multi-core.