Mastercard SDE-1 JAVA OOPS Interview Experience
Summary
I applied for an SDE-1 Java OOPS position at Mastercard via a referral and went through a 4-week interview process. Despite making it through multiple technical rounds, I received a rejection, which HR attributed to a lack of balance across competencies, possibly due to my primary backend experience being in Node.js instead of Java.
Full Experience
My Mastercard SDE-1 Interview Experience
I recently had an interview experience for an SDE-1 role at Mastercard in Pune. I applied through a referral, which was lucky this time as my previous two applications hadn't yielded any response. The entire process took about 4 weeks.
HR Round
My journey started with an HR call. It was a pretty casual chat where we discussed my current role, tech stack, and salary expectations. The HR representative also explained the full interview process and confirmed that the job location would be Pune. It felt like a basic fit and interest check.
Tech Round 1 (Screening)
This was the initial screening round, which was quite conceptual and straightforward. I was asked to explain OOPs to a 5-year-old, which was an interesting way to test my understanding. Following that, we delved into a system design problem: I had to design a car system, considering various models, engines, and applying appropriate design principles/patterns. The round concluded with a coding challenge to print prime numbers within a given range.
Superday (3 Non-Eliminatory Rounds)
The Superday was intense, comprising three non-eliminatory technical rounds back-to-back.
Round 2 (Tech SME)
In this round, the interviewer focused heavily on OOPs, specifically asking me to elaborate on the four pillars of OOPs with examples. For coding, I was given the 'Valid Parenthesis' problem and asked to handle all edge cases. We also spent a significant amount of time discussing my current projects, and I was tasked with implementing a basic LinkedList.
Round 3 (Bar Raiser)
This round was quite challenging. I was given two buggy Java code snippets to debug—one related to file handling and another involving the Singleton design pattern. The main coding question was 'Decode String,' a well-known LeetCode problem. Unfortunately, I struggled and couldn't complete it under the pressure.
Round 4 (Hiring Manager)
The final round was with the Hiring Manager. It covered Java and OOPS basics. For coding, I was given what was described as an 'easier version' of the Longest Increasing Subsequence problem. The rest of the discussion centered around my projects, achievements, and my reasons for wanting to join Mastercard.
Result
About a week after the interviews, I received a polite rejection. The HR representative mentioned that they selected a candidate who showed a more balanced performance across all competencies. I believe my primary backend experience in Nest.js (Node) rather than Java might have been a contributing factor to this outcome.
Interview Questions (9)
I was asked to explain the core concepts of Object-Oriented Programming (OOPs) in a simplified manner suitable for a 5-year-old.
Design a car system, including its various models and engine components, by applying appropriate design principles and patterns.
Write a program or algorithm to print all prime numbers that fall within a specified numerical range.
I had to explain the four fundamental pillars of Object-Oriented Programming (OOPs) and provide concrete examples for each.
Implement the fundamental structure and basic operations of a singly linked list data structure.
Identify and fix bugs in two provided Java code snippets. One snippet dealt with file handling, and the other involved the Singleton design pattern.
Solve a variation of the Longest Increasing Subsequence (LIS) problem, explicitly stated as an 'easier version'. The task involves finding the longest subsequence of a given sequence such that all elements of the subsequence are sorted in ascending order.