Rock Interview Java Trainee interview questions

It was started when I downloaded their Mobile app just to try and see how it works (I have that habit). It gave me a free mock interview offer on their app with an industry expert, which gave me a good confidence on what i learnt from Hyderabad in my training time. After some days, I got a call from the same girl from Operations team of this company, saying we have an opportunity for Java Trainee and I am a good fit for that. After which my technical interview happened, which was pretty simple (i have added questions below), time taken was around 15 minutes and the next call was from Operations team saying you are selected and our manager would call you regarding salary discussion.