I recently gave interview for Rakuten for JAVA Dev.The interviewer joined on time and we started off with a good conversation.

Questions)
He asked me to write Singleton class code and then started modifying it by making it thread safe.He then asked some very basic java question which one can't remember easily but again everything was good at this moment of time.

At end of 20 min he asked me to write code for finding Kth largest element in an array.
I initially gave a brute force approach to start with and talked to him about Sorting techniques
I then optimized the code with Heap logic.

He started laughing saying that why you didn't told heap logic first rather than sorting technique.It was bearable at this moment of time.

Then after I wrote the code for heap logic and showed.
After discussing the logic he started laughing very badly saying what is this logic this won't work , why are you adding and removing in heap as it will have no effect and what not.

I said him calmly that lets compile the code on editor and I compiled with initial test he gave and it passed successfully.Then after he started making all possible test cases and my code passed all his test cases after that his face was like anything.

It seemed that he hasn't had any DSA knowledge.But it was really frustrating when he was laughing at my code.

I rejected the further interviews from front and never gave other rounds.