You have to attend all rounds, and at the end, they will either select or reject.

This feels unnecessary, but that's the process.

I was not selected and kind of knew after the 3rd or 4th round. But I'm posting the kind of questions asked in the process if it helps.

Oracle OCI Principal Engineer Interview Process

1. Screening Round: Past projects and a coding question (LeetCode easy to medium) to sum two large decimal numbers.
2. Class Design Question: Minesweeper game.
3. Managerial Interview: Purely behavioral and past projects.
4. Coding Round (LeetCode easy to medium): Sliding window log rate limiter based duplicate rejection.
5. Bartender Round: Behavioral question.
6. HLD Design Round: IoT data collection system.