What is the output of this code? And please explain I'm not able to understand.. Explain how this program works

Question

https://code.sololearn.com/cwlZWTnxUS80/?ref=app

Answer 1

My answer is the comment on your code =)

Answer 2

In generics we can give only class names but I didn't create any T class.. what is that T class provided in the generics??