Is this Runnable safe from memory leak?

Question

I am a total beginner in Java and have created a simple Java Android snippet where in a Runnable after 1,5 seconds I change the TextView from Hello World<

Answer 1

I have a doubt if there's absolutely no memory leak whenever device orientation occurs.

It could be. For 1.5seconds. After the queue is emptied the handler can be garbage collected, and also the old Activity. To be safe override onPause, and call handler.removeCallbacks(null); to clear the Handler's queue