Pluang | SDE-3 | JAVA Backend | Interview Experience

My interview for the SDE-3 Java Backend role at Pluang started with a typical introduction where we both shared backgrounds, and I discussed my current role, project tech stack, and responsibilities for about 15 minutes.

Following the introduction, the interviewer moved on to Data Structures & Algorithms. I was given two well-known LeetCode problems. The first was Evaluate Reverse Polish Notation, which I successfully implemented using a Stack. The second problem was Koko Eating Bananas, for which I presented a binary search approach.

The discussion then shifted to System Design, specifically focusing on Kafka. I was asked a series of questions:

• What is Kafka? I explained its architecture, detailing producers, brokers, topics, partitions, and consumers.
• Acks in Kafka (acks=0, acks=1, acks=all)? I elaborated on the trade-offs between reliability and performance for each acks setting.
• Message Ordering in Kafka? I described how message ordering is maintained within partitions.

Next, the conversation moved to Redis. The questions included:

• What data structure have you used? I mentioned mainly using Key-Value pairs (String type) for caching.
• Did you use Lists, Sets, Hashes, Sorted Sets? I clarified that my current use cases primarily revolve around simple key-value stores.
• By default, which data structure does Redis use? I explained that key stores can map to multiple data types, with String being the default if no specific type is mentioned.
• Have you heard of CROSSSLOT error? What is it? I explained the concept of CROSSSLOT errors in Redis Cluster, which arise when multi-key commands involve keys that don't hash to the same slot.

Unfortunately, time ran out, so the interviewer provided quick feedback at the end of the session.