Round 1 — Java & Spring Boot Fundamentals (~1 hour)
Entirely conceptual — no coding, just deep discussion.
Java:
- JVM internals and Java memory management
- Garbage Collection strategies
- Concurrency
- Internal working of HashMap (explanation, no implementation)
Spring Boot:
- Spring vs Spring Boot differences
- Inversion of Control (IoC)
- Dependency Injection
- Types of annotations
Difficulty: Easy. A straightforward fundamentals discussion.
Round 2 — DSA + HLD + Puzzle (~1 hour)
DSA: Rotate Array (easy LeetCode problem) in Java.
HLD: Design a system like RedBus.
- Searching buses by location and time
- Concurrency — handling two users booking the same seat simultaneously
- Notification system design
- Interviewer seemed satisfied with the approach.
Puzzle: Two candles, each burns in exactly 1 hour. Measure exactly 45 minutes. (Light one candle both ends + another one end. When the first burns out = 30 min, light the second candle's other end = remaining burns in 15 min. Total 45.)
Difficulty: Easy to Medium.
Round 3 — Director / Managerial (In-Office, 45 min)
Felt more like a professional discussion than an interview.
- Current project and responsibilities
- How I'd approach migrating a monolith to microservices
- How Agile works in practice
- Open discussion on AI — how I use it day-to-day, its limitations, pros/cons, and whether it's useful in every scenario
The AI discussion took up most of the round — clearly they value engineers who use AI thoughtfully.
Round 4 — HR
Standard HR round — salary expectations and basic details.
Tips for Rakuten
- Java/Spring fundamentals are heavily tested — JVM, GC, concurrency, HashMap internals, IoC/DI. Know these cold.
- DSA is easy-medium — don't over-prepare LC Hard. Focus on clean implementation of common problems.
- HLD focuses on concurrency — especially seat booking / double-booking scenarios. Know optimistic vs pessimistic locking.
- Prepare for AI discussions — have a thoughtful view on where AI helps and where it doesn't.
- Keep a puzzle or two ready — classic logic puzzles show up.