PayU

Role: SDE-2 Backend

College: Not Specified

Interview Date: September 2024

Interview Type: Full-Time (Off-Campus)

Result: Offered

Difficulty: Easy-Medium (DSA), Medium (System Design, Core Java/Spring Boot)

Rounds: 4 rounds

Topics Asked: Data Structures, Algorithms, Core Java, Spring Boot, Low-Level Design (LLD), High-Level Design (HLD), Behavioral

Experience:

The candidate reached out to a recruiter for an SDE-2 Backend role. The interview process had four rounds and took almost three weeks.

First Round (DSA Round): Two LeetCode Easy-Medium level DSA questions were asked. One question involved finding the maximum score achievable after performing an operation 't' times on an array, with a hint for a max heap optimization.

Second Round (LLD Round): This round focused on Low-Level Design. The interviewer gave a problem statement related to a payment gateway and asked for an LLD. The candidate started by understanding requirements, then identified entities and attributes. Discussions included class diagram relationships (UML), design patterns (Strategy, Factory, Observer), and SOLID principles. The interviewer seemed content, but suggested a separate Core Java and Spring Boot round as the candidate initially struggled with basic core Java questions.

Third Round (Core Java and Spring Boot Round): This 30-45 minute round covered multiple questions on Core Java and Spring Boot.

• Pillars of OOPs and functional interfaces.
• Major difference between interface and abstract class.
• Profiling in Spring Boot, ControllerAdvice, and difference between Controller and RestController.
• Why use @Service and @Repository annotations, and what if only @Component is used?
• Dependency Injection in Spring Boot, types of bean scoping and their definitions.

This round went well.

Fourth Round (Hiring Manager - HM Round): This round primarily involved discussions about the candidate's past work experience, role, and the product development lifecycle in their current company (from requirements gathering to release). Questions were also asked about authentication and authorization, how validation works, and measures taken for API request body validation. Encryption and decryption methods used by the candidate and their working were also discussed.

Overall Experience: The HM round went decently, and the recruiter provided positive feedback the same day, indicating an offer for the SDE-2 Backend position. The candidate shared resources for preparation, including Striver's A-Z DSA Sheet, Interview-Prep for company-wise questions, and Shrayansh Jain's YouTube playlist for LLD/HLD.