Walmart Interview Experience | Software Engineer III | Java Backend Developer (Sept 2025)
Summary
I recently interviewed at Walmart for a Software Engineer III, Java Backend Developer position. I successfully navigated the DSA and LLD rounds, and I am currently awaiting confirmation for the next stage, the Hiring Manager round.
Full Experience
I recently interviewed at Walmart for a Software Engineer III (Java Backend Developer) role. Here's a breakdown of my experience:
Round 1: DSA
This round was with a Senior Software Engineer. After a quick introduction, we moved straight into problem-solving.
- Coin Change (Dynamic Programming): I discussed recursive with memoization and tabulation approaches, optimizing the solution and answering all follow-ups.
- Course Schedule (Graph / Topological Sort): I solved this using a BFS (Kahn’s Algorithm) approach. We also discussed DFS cycle detection as a follow-up.
I successfully solved both problems within the allotted time and cleared this round.
Round 2: Java + LLD
This round was with a Staff Software Engineer and was split into two parts.
Part 1: Java (20 mins)
We covered OOPS fundamentals, the internal workings of HashMap, multithreading concepts like the volatile keyword and its use cases, and some general Java basics.
Part 2: LLD
I was asked about design patterns I had used recently. We then had a deep dive into the Strategy Design Pattern. The interviewer presented a real-world scenario involving a Payment Gateway (UPI, Bank Transfer, etc.) where the strategy is selected at runtime. I implemented a basic code structure and handled follow-up questions effectively.
This round felt like I performed somewhere between average and above average. I'm currently waiting for HR confirmation; if cleared, the next step will be the Hiring Manager Round.
Overall, the interviewers were friendly and focused on a deep understanding of concepts. The DSA round involved standard LeetCode medium-level problems, and in the LLD round, a clear explanation of design choices was more crucial than just writing code. I'll update once I hear back from HR.
Interview Questions (3)
Given an array of coin denominations and a target amount, return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. I discussed recursive with memoization and tabulation approaches, optimizing the solution and answering all follow-ups.
There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are also given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course bi first if you want to take course ai. Return true if you can finish all courses. Otherwise, return false. I solved this using a BFS (Kahn’s Algorithm) approach and discussed DFS cycle detection as a follow-up.
Design a Payment Gateway system that supports various payment methods (e.g., UPI, Bank Transfer). The system should be able to select the appropriate payment strategy at runtime. I was asked to implement a basic code structure and handle follow-up questions.