Mockito: When is @Mock object get initialized and which constructor it calls

I'm trying to figure how mockito is working behind in order to debug. I was wondering for the object with @Mock annotation, when is it initialized? Like, before @Before or after @Before?

And if there're several different constructors, how is mockito determines which constructors to call?

And if I use jmockit @Mocked instead, are there any different answers of the questions above?

Thank you!