Reliance AJIO Interview Experience for SDE

First, there was a call from a recruiter confirming my experience and the details mentioned on my resume. Then after a week, the interview was scheduled for the first coding round.

All rounds were virtual on a video call in screen-sharing mode.

Round 1: Coding DSA

First, he asked me to brief you about myself and there was a little discussion about my projects and their applications. After that he quickly jumped to the question and asked me a SET data structure question, I started from the naive approach and gave him the optimal solution.

• longest-consecutive-sequence

Input: nums = [100,4,200,1,3,2]
Output: 4
Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4.

After that, he asked another question mentioned below.

• Merge Intervals

Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlap, merge them into [1,6].

I have given him the optimal solution for both questions. Then after another round was scheduled.

Round 2: OOPs + HL Design 

This round was mostly focused on the design of my projects, which design patterns I have used, like Factory Pattern, Observer Pattern, and Builder pattern, Since I have used them in my project, I answered him thoroughly and the interviewer was pretty much convinced

He also asked about the different Map implementations available in Java like HashMap, TreeMap, and LinkedHashMap. The interviewer wanted to know the use case of each map and their pros & cons.

Then the interviewer asked me about the OOPs’ concepts of Abstraction, Polymorphism, Encapsulation, and Inheritance. The difference between Abstraction Class and Interface.

Then interviewer gave me a question to design the secure Login System for an application with OTP support. I created the HLD on the ExcaliDraw site. The interview was supportive and asked a couple of cross questions and corrected the design to enhance security.

Round 3: Tech-Lead Hiring Manager + HLD + LLD

The interviewer started with a brief introduction and quickly jumped to my resume and started discussing my project. 

Since I have worked on HazelCast Cache, he asked me basic questions like:

1. Why the cache is required in the application?
2. How does cache work in distributed microservice architecture?
3. What are the cache replacement algorithms?
4. What is an In-Grid Memory cache? 
5. What are the other open-source caches service available in the market?
6. Why HazelCast, Why not Redis? 

The interviewer kept on going into the details(1, 2, and 3 questions answered) and finally,(4, 5, and 6 questions I did not answer) I had to say, I don’t know the very deep details of how HazelCast internally works but I will read. The interviewer was okay and moved to another question.

Then the interviewer asked me about the SQL and NoSQL DataBase differences also which one to use under which use case. Then he asked me CAP theorem.

Since I have worked mostly on SQL, I told an interviewer that I am more comfortable with SQL. After that, he asked me how Indexing works in RDBMS.

A few questions asked me about Microservice Architecture :

1. What are the advantages of Microservice?
2. What are the disadvantages of Microservice?
3. What is the circuit breaker design Pattern in Microservice?
   

I have answered all the microservice-related questions because mostly my all projects are in microservice and I had the 3 years of experience in that.

Then the interviewer asked me, do you have any questions? 

I asked some questions you asked me about HazelCast, that I don’t know. since I had worked on accessing data only through Hazelcast Cache and now I will go through it and learn more about another in-grid memory cache available. The interviewer said It is fine no problem.

The evaluation was done in this round and the next day I got a congratulations mail from HR. 

Finally, I got the offer for SDE II at Reliance AJIO in Bengaluru, Karnataka.

Thank you, GeeksForGeeks for providing study material. It helped a lot.