Oracle Software Engineer interview questions

I reached out to hiring manager. He gave me initial call and he informed me about the product and overall interview process. Then I received a phone call interview invite. It was a 45min round where we programmed easy level leetcode question on coderpad. After that I received onsite interview invite. It was my 4th onsite interview and I cleared all 3 previous interviews. But this interview was the worst interview experience ever. Onsite interview started with a leetcode question LRU Cache which I solved quickly on white board - interviewer was kind and we had a very good discussion on team and their project. Second round of interview was a system design interview. The interviewer was very rash. He started laughing as soon as he entered the room. He gave me a question and asked me to use white board to explain. As soon as I started, he said sit down and changed his mind to ask me about some random sorting algorithm. I explained that and he started looking at my resume and started laughing again. I really didn't understand his behavior. Third round was a lunch interview with hiring manager. He asked me about some behavioral questions and after lunch we sat together to answer some oracle values questions. He asked me to a leetcode question to find if a number is perfect square or not. Which I solved quickly on whiteboard. It was a good interview overall. The last interview was again very disappointing. Interviewer was a senior software engineer. He gave me a simple array question. When iterating over array I incremented index like this 'index++' and as soon as I did that he started arguing with me saying this will increment index first and then reach to next index. Initially I thought he is trying to confuse me but later on it turned out that he didn't know. But he didn't agree to what I said. Anyways. Then he asked me to change arrays to list because list will give me O(1) look up but not arrays - this is what he said me during interview. I didn't know what to do there. I changed array to list, lol. The last one was behavioral with a member of other team. It was a good interview with many behavioral questions. Overall the interview process was very disappointing. If the interviewer lacks with the fundamentals it is very difficult to clear the interview as he will never listen to you. I travelled to Seattle a month ago but still didn't receive my reimbursement.

Interview process contains 3 rounds. 2 technical interviews followed by hr interview. I got rejected in the second technical round. They asked questions related to my projects and some technical questions