Recently I interviewed for the IC-2 Backend Engineer role at Oracle, and here’s my experience.
Sharing this so it helps others preparing for Java + Kafka + system design rounds.

🟦 Round 1 — Technical Interview (Projects + DSA)

A single, in-depth technical round focusing primarily on Kafka, system architecture, and reliable system design.

What was covered?
🔹 Project Deep Dive

End-to-end explanation of my project

Detailed discussion on architecture

How the system scales under load

How different components communicate

Why certain design decisions were made

🔹 Kafka (Major Focus Area)

They went deep into Kafka producer–consumer flow:

Implementing idempotency at producer level

Implementing idempotency at consumer level

Handling retries, offsets, duplicate messages

At-least-once vs Exactly-once semantics

Using message keys, partitions, and commit strategies

This was the most detailed portion of the round.

🔹 System Architecture + Scalability

How to scale microservices horizontally

Handling millions of messages

API load balancing

Fault tolerance & retries

Distributed design basics

🔹 DSA

A string-based DSA question was asked at the end.
(Moderate level, focused on clean logic and reasoning.)

🟦 Feedback & Result

HR informed that:

I cleared the round Feedback was positive But the team froze the opening, so they will reconnect once another opportunity opens.

Practical project-based thinking

A good interview experience overall, even though the position was put on hold.