SDE-1 @PeopleStrong | Round1 | Java Backend Developer
Summary
I interviewed for an SDE-1 Java Backend Developer role at PeopleStrong and successfully cleared the first round, which covered System Design, Data Structures & Algorithms, Core CS, and Java backend fundamentals.
Full Experience
I started the interview with a self-introduction, followed by a detailed resume walkthrough where the interviewer picked specific topics from my experience for Q&A. The round was comprehensive, focusing on Data Structures & Algorithms, System Design, and core Computer Science and Java backend questions.
Interview Questions (12)
Monolithic vs. Microservices Architecture
I was asked to explain the key differences between Monolithic and Microservices architectural styles, outlining their respective advantages and disadvantages.
CAP Theorem Explanation
The interviewer asked for an explanation of the CAP Theorem, requiring me to define Consistency, Availability, and Partition Tolerance, and discuss its implications in distributed systems.
ACID Properties of Transactions
I had to describe the ACID properties (Atomicity, Consistency, Isolation, Durability) as they apply to database transactions.
Reducing API Latency
I was asked to discuss various strategies and techniques to reduce API latency, including topics like caching, database optimization, asynchronous processing, Content Delivery Networks (CDNs), and load balancing.
Resilience4j Circuit Breaker Pattern
The question involved explaining the working of the Circuit Breaker Pattern, specifically in the context of Resilience4j, and discussing its practical use cases in distributed systems.
SQL Indexes
I needed to explain different types of SQL indexes (Clustered, Non-Clustered, Covering, Composite), their advantages and disadvantages, and the underlying data structure used (B+ Tree).
Primary Key vs. Foreign Key
I was asked to explain the differences between a Primary Key and a Foreign Key in relational databases.
final vs. finally in Java
I had to explain the difference between the final keyword and the finally block in Java.
JWT Token (Authentication & Authorization)
The interviewer asked what a JSON Web Token (JWT) is, how it works, and its role in authentication and authorization processes.
Authentication vs. Authorization
I was asked to explain the key differences between authentication and authorization in the context of security.
@RestController vs. @Controller in Spring
I had to explain the differences between the @RestController and @Controller annotations in the Spring Framework.
Valid Parentheses
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', I had to determine if the input string is valid. An input string is valid if: open brackets must be closed by the same type of brackets; open brackets must be closed in the correct order; every close bracket has a corresponding open bracket of the same type. I was required to dry run the solution with inputs provided by the interviewer, covering multiple test cases and edge cases.
Preparation Tips
My preparation focused strongly on System Design basics and Java backend concepts. I paid particular attention to database optimization, especially indexes. I also made sure to understand Resilience patterns and the JWT flow. The DSA problem was of medium difficulty, primarily a stack-based problem.