posted 9 years ago
Correct, Observables are not threads, and they do not create any new threads. When notifyObservers() is called, the Observable calls update() for each Observer in the same thread that was used to call notifyObservers(), sequentially. There may still be other things happening in parallel if your program is already using multiple threads. An Observer can function in a multi-threaded environment, but it does not create any new threads itself.