Profile:
Education: B.Tech (Tier 1)
Experience: 2.6 years
Application Process: I applied through the Walmart job portal using a referral and sent over 35 applications using a Walmart employee's email.
Round 1: Data Structures & Algorithms (DSA)
1. Find an element in a reverse sorted array.
-Solved using binary search.
Follow-up: Handling duplicate elements – I proposed some approaches but couldn't implement an optimized solution on the spot.
2. Course Schedule I.
-Solved using topological sort.
Round 2: Core Java
Singleton classes – Explained their real-life use cases and wrote the code.
Keywords (final, static, transient) – I wasn’t familiar with transient at the time.
How to make a class immutable?
Error handling – Discussed checked and unchecked exceptions.
Can you leave a catch block empty? Can this be used in a static method?
I made a silly mistake while answering these.
Deadlocks – Explained what they are and how to prevent them.
Multithreading problem:
Given an attribute that needs to be incremented by two threads until its value reaches 5000, I was asked to write the code.
What is AtomicInteger? What is the String pool?
Thread-related concepts:
Thread join and thread pool questions.
Difference between Hashtable and ConcurrentHashMap
I was prepared for HashMap vs. Hashtable but didn’t know this difference.
Tip: Watch Shreyansh Jain’s Java videos on YouTube. I watched them at 3.5x speed the day before the interview, which helped me answer many questions.
The interviewer was very supportive throughout the round.
Round 3: Hiring Manager (HM) Interview
Resume-related questions.
Discussion on my current project.
Threading & heap dump-related questions.
API optimization:
How to optimize an API that makes multiple API calls, then checks the cache, and finally queries the database?
Behavioral question:
Why do you want to leave your current company?
This round was scheduled for 1 hour but lasted 30 minutes. It didn’t go as well as I had prepared for different topics, but the hiring manager was very chill. Fortunately, I received positive feedback.
Round 4: HR Interview
Behavioural Questions. No Compensation talk.
**Update **
I received the offer letter after 20 days. They gave me a low offer since I didn’t have any other offers. I accepted it but will try for opportunities at other companies.