Starting an activity after 1000ms from a splash screen with Runnable and Handler().postDelayed
I don't like name startTheTransitionAfterTheSplashScreen. Too long, you are already in SplashScreen. Maybe startTransition or startTransitionafter1second.

Using handler is fine, but what if user manages to change orientation during that 1 second? Activity gets destroyed and recreated. Now you have 2 active handlers and I expect ActivityJustAfterSplashScreen will be called 2 times.

I suggest keeping reference to handler so that you can cancel in onDestroy - handler.removeCallbacksAndMessages(null).