Kellton Technologies Software Developer Interview: Rounds, Questions and Preparation

What the job involves

As a Software Developer at Indian IT services companies like Kellton Technologies, you will work on client projects building, testing, and maintaining web or enterprise applications. Day to day involves writing code in languages such as Java, Python, or JavaScript, fixing bugs, participating in stand-ups, and coordinating with senior developers and QA teams. You may also support deployment, documentation, and minor enhancements based on client requirements.

Role and Technical Knowledge

1. 1

   Explain the difference between a process and a thread in an operating system.

   A strong answer defines both, mentions memory sharing, and gives a simple example like a browser process with multiple tabs as threads.

2. 2

   What is normalization in SQL, and why is it used in IT services projects?

   Cover 1NF, 2NF, 3NF briefly, and explain how it reduces redundancy and improves data integrity in client databases.

3. 3

   How does a REST API work, and how would you consume one in your code?

   Mention HTTP methods, status codes, JSON payloads, and a basic example using fetch or requests library.

4. 4

   What is the difference between an abstract class and an interface in Java or C#?

   Explain multiple inheritance support, default methods, and when to choose one over the other in service-based projects.

Practical Scenarios

1. 5

   You are assigned a bug in a legacy codebase with no documentation. How do you start fixing it?

   Describe reproducing the bug, adding logs, tracing the flow, writing a small test, and asking senior developers for context without being a blocker.

2. 6

   A client asks for a feature that will take two weeks, but your manager wants it in three days. What do you do?

   Show that you communicate trade-offs, propose a minimal viable version, and escalate timeline risks early rather than silently overworking.

3. 7

   How would you optimize a slow SQL query that runs on a large table?

   Mention checking indexes, avoiding SELECT *, using EXPLAIN plan, and limiting joins or subqueries where possible.

4. 8

   Your code works on your machine but fails in the testing environment. How do you debug it?

   Compare environment variables, dependency versions, configuration files, and logs; mention containerization or CI differences if relevant.

Behavioural and HR Questions

1. 9

   Why do you want to join a mid-sized IT services company instead of a large product firm?

   Highlight exposure to multiple clients, faster learning, broader responsibilities, and willingness to adapt to different technologies.

2. 10

   Tell me about a time you worked in a team on a college project and faced a conflict.

   Use STAR format, focus on how you listened, adjusted roles, and delivered the project on time without blaming others.

3. 11

   Are you willing to relocate or work in different shifts based on client requirements?

   Answer honestly but show flexibility; mention that you understand IT services often require shift or location adjustments.

4. 12

   Where do you see yourself in three years in this role?

   Express interest in becoming a reliable developer, learning new stacks, and possibly leading a small module or mentoring juniors.

Coding and Problem Solving

1. 13

   Write a function to check if a string is a palindrome without using built-in reverse functions.

   Use two pointers or a loop; explain time complexity O(n) and handle edge cases like empty string and case sensitivity.

2. 14

   How would you find the first non-repeating character in a string?

   Use a hash map or array to count frequencies, then iterate again; mention O(n) time and O(1) space for fixed character set.

3. 15

   Given an array of integers, find two numbers that add up to a target sum.

   Describe brute force O(n^2) and optimized hash map O(n) approach; code the optimized one and test with a small example.

4. 16

   Explain how you would reverse a linked list iteratively.

   Walk through pointer manipulation with prev, current, and next; mention edge cases like empty list or single node.