I'm writing a service that uses JNA to delegate work from Java to a native C++ library. The C++ library makes an async call for a computationally expensive task, and then gets a callback (on a different OS thread) when that task is complete. I would like to route the result of this work back to the correct thread in JVM.

What I'm wondering is can I be guaranteed that the JVM thread id will always have a one to one mapping with a native thread\_id? I.e. if I record the thread id in C++ via

```
std::this_thread::get_id()

```

then kick off some expensive work and block on a cv, that the thread will still be there once the work is complete, and that I'll be able to return results to JVM correctly. Will any behind-the-scenes JVM work like JIT, GC, or stop the world collections be causes for concern with this pattern?