Oracle Senior Software Engineer interview questions

First recruiter finds my resume on Linkedin and she gave me a call, described what job it is, have a simple English communication, and asking me to think about for days. Then 2 days after we have another call, and I gave her my resume, and the process began. About 1 week later I got an phone call from the team, after about 30 minutes phone call, we have a 2-3 hours interview. This is first round interview, 4 rounds including 1 paper test. 1 week later I've been told I passed the 1st round, and next round will be an online meeting with managers in US. It was last about 1 hour 2 weeks later I got the offer.

Applied online and got a call two weeks later. Basically going through my work experience and was told I will be contacted shortly. A week later HR arranged for in person interview that lasted 3 hours. Mostly technical questions. Abstract vs interface etc.