Corporate Infotech Pvt Ltd interview experience Real time questions & tips from candidates to crack your interview

Java Full Stack Developer

Corporate Infotech Pvt Ltd

1 rounds | 6 Coding problems

Vaibhav

Experienced | Nov 2025

Rejected

Interview preparation journey

Journey

I started with basic programming concepts and gradually moved toward backend development by building small applications and APIs. Initially, understanding how databases, servers, and APIs work together was challenging, but working on real features helped me learn faster. Over time, I gained experience with Python, Django, REST APIs, and SQL, and began contributing to production systems in the travel domain, where reliability and performance are critical. Debugging live issues and handling real user data improved my problem-solving skills and confidence. Alongside my job, I consistently revised fundamentals and practiced coding questions to strengthen my interview readiness. Reaching this interview stage itself was the result of consistent learning, hands-on experience, and perseverance when concepts felt difficult at the beginning.

Application story

I learned about this opportunity through a walk-in interview announcement shared online and via email. Since it was an open walk-in, I directly visited the interview location on the given date with my resume. After registering at the venue, I waited for my turn, and the interview process was conducted on the same day. The overall process was straightforward and did not involve any prior shortlisting, which made it easy for candidates to participate and showcase their skills directly.

Why selected/rejected for the role?

I was rejected mainly because the role required stronger hands-on experience in their specific full-stack technologies, especially on the frontend side, where I have less exposure compared to the backend. Although my backend fundamentals were strong, the company was looking for someone who could handle both layers more independently from day one. This experience helped me realize the importance of building balanced full-stack skills alongside backend expertise.

Preparation

Duration: 1 month

Topics: Data Structures, Algorithms, OOPS Concepts, REST API Design, Database Queries and Joins, Basic System Design, Java Backend Fundamentals

Tip

Tip 1: Revise core concepts daily and focus more on understanding than on memorizing solutions.

Tip 2: Practice coding problems related to arrays, strings, and basic algorithms consistently.

Tip 3: Revise backend concepts such as API flow, database interactions, and common design patterns before interviews.

Application process

Where: Naukri

Eligibility: There were no strict eligibility criteria, but basic knowledge of backend development and having development projects on the resume were preferred. (Salary Package: 13 LPA)

Resume tip

Tip 1: Clearly mention your tech stack and explain exactly what you worked on in each project.

Tip 2: Keep the resume short and relevant to the role, instead of adding unrelated technologies.

Tip 3: Include real internship or job experience if available, not just academic projects.

Interview rounds

Round

Easy

Face to Face

Duration120 minutes

Interview date29 Nov 2025

Coding problem6

1. System Design

What is API rate limiting, and why is it important in backend systems?
How can rate limiting be implemented at scale?

2. System Design

Explain how background jobs and message queues work in web applications.
Why are queues useful for improving reliability?

3. System Design

How would you design logging and monitoring for a production backend system?
Which metrics are important to track?

4. System Design

Explain how feature flags are used in large applications.
How do they help enable safe deployments?

5. Longest Substring Without Repeating Characters

Moderate

30m average time

65% success

0/80

Asked in companies

Given a string input of length n, find the length of the longest substring without repeating characters i.e return a substring that does not have any repeating characters.

Substring is the continuous sub-part of the string formed by removing zero or more characters from both ends.

Problem approach

Step 1: First, I considered checking all substrings and verifying if the characters were unique, which would take O(n²) time.

Step 2: Then I used the sliding window technique with two pointers and a set to track unique characters in the current window.

Step 3: When a duplicate character was found, I moved the left pointer until the window again contained only unique characters.

Step 4: I updated the maximum length during each valid window. This reduced the time complexity to O(n).

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6. Next Greater Element

Easy

10m average time

90% success

0/40

Asked in companies

You are given an array 'a' of size 'n'.

Print the Next Greater Element(NGE) for every element.

The Next Greater Element for an element 'x' is the first element on the right side of 'x' in the array, which is greater than 'x'.

If no greater elements exist to the right of 'x', consider the next greater element as -1.

For example:

Input: 'a' = [7, 12, 1, 20]

Output: NGE = [12, 20, 20, -1]

Explanation: For the given array,

- The next greater element for 7 is 12.

- The next greater element for 12 is 20. 

- The next greater element for 1 is 20. 

- There is no greater element for 20 on the right side. So we consider NGE as -1.

Problem approach

Step 1: Initially, I considered a brute-force approach, where for each element I would scan the right side to find a greater element, resulting in O(n²) time complexity.

Step 2: Then I realized this could be optimized using a stack. I traversed the array while maintaining a stack of elements whose next greater element had not yet been found.

Step 3: When the current element was greater than the top of the stack, I popped elements and assigned the current value as their next greater element.

Step 4: The remaining elements in the stack were assigned -1. This approach worked in O(n) time.

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