Epam Systems Interviews

I recently had a Python interview with EPAM, and I wanted to share my experience in case it helps anyone else preparing for similar roles. The interview was quite comprehensive, delving deep into core Python concepts, specifically advanced features and object-oriented programming. We also spent significant time discussing system design, particularly focusing on microservices architecture. I found the questions to be practical, often requiring me to explain concepts with code examples or discuss real-world applications and trade-offs.

I am currently working as a Senior Software Engineer in a fintech company with a total of 5.5 years of experience. Below is my interview experience with EPAM.

Round 1

This round involved Java-based coding tasks and conceptual questions related to Java 8 features and collections.

Coding Questions: Use Streams to implement below:

1. Print the list of all employees

list.forEach(e -> System.out.println(e.getId() + " " + e.getName() + " " + e.getDesignation()));

2. Collect a list of employee IDs divisible by 2

List<Integer> result = list.stream()
    .filter(e -> e.getId() % 2 == 0)
    .map(Employee::getId)
    .collect(Collectors.toList());

3. Sort the employee list in ascending and descending order of ID

Collections.sort(list, (a, b) -> Integer.compare(a.getId(), b.getId()));

More in depth questions were asked from below topics.

• Functional Interface
• Collectors & Optional
• map vs flatMap
• Method references
• System.out.println() vs System.out::println
• Object::printVal
• Reentrant Locks
• Blocking vs Non-blocking calls
• CompletableFuture Object
• Marker Interface (Serializable, Cloneable)
• equals() and hashCode() contract
• TreeSet vs TreeMap
• Comparable vs Comparator
• Deep Cloning vs Shallow Cloning
• Heap, Stack, Metaspace
• Classpath
• Checked vs Unchecked Exceptions
• SQLException Handling
• FileHandler
• String Comparison in Java:

String a = new String("Vijai");
String b = new String("Vijai");
String c = "Vijai";
String d = "Vijai";

System.out.println(a == b); // false
System.out.println(a.equals(b)); // true

• Coding Question: Find the longest Substring Without Repeating Characters

Example Input & Output:

Input: "abcadcbb" → Output: 4 (Substring: "bcad")

Input: "pwwkew" → Output: 3 (Substring: "wke")

Optimized solution: O(n) time complexity.

Round 2

This round covered dependency injection, Spring Boot, transaction management, and system design.

Topics Covered:

• Spring Boot Starter Dependencies
• Spring Actuator (Health Check, Logging, Tomcat)
• Dependency Injection in Plain Java (without Spring)
• @Primary vs @Qualifier
• @Transactional
• SOLID Principles
• Dependency Inversion Principle
• Liskov Substitution Principle
• Spring Annotations
• @ControllerAdvice
• AOP (@Before, @After)
• Singleton Pattern & Thread Safety
• Factory Pattern & Use Cases
• Strategy Pattern in Java
• Observer Pattern
• Mockito & Unit Testing Best Practices
• Custom Exception Handling in Spring
• Handling Service Failures in Distributed Systems
• Microservices Communication Strategies
• Multithreading and Concurrency
• Reentrant Locks vs Synchronized Blocks
• Database Transactions & ACID Properties
• Event-Driven Architecture
• LLD design (Don't remember the exact question)

Verdict: Ghosted after round 2. Was told Round 3 will be held later as feedback of Round 2 was neither positive, not negative.

I recently went through the interview process with EPAM for a Senior Software Engineer role. The focus of the position was on Data Structures and Algorithms with Java. I'm pleased to share that I successfully received an offer after completing all rounds. The interview process was comprehensive and included a coding round, a systems design round, and a hiring manager round.

Coding Round: I was presented with a problem that required me to implement a simple voting system.

Systems Design: This round had a dual focus. First, I was asked to design a small-scale screen broadcast system capable of playing, replaying, changing, or scheduling ads/videos across multiple screens. Following that, the discussion shifted to microservice architecture patterns such as API Gateway, BFF, Circuit Breaker, Database per Service, Event-Driven, and Saga pattern. We also touched upon the Richardson Maturity Model, REST API grading, and the key differences between SOAP and REST.

Hiring Manager Round: This round began with a system design problem where I had to design a train ticket booking application. The emphasis was on high-level design, Back-of-the-Envelope estimation, and creating an efficient database design to find available trains and seats between a source and destination. Additionally, I was questioned on the 12-factor principles of microservices and asked about design patterns I have experience with. The round concluded with a brief discussion regarding project locations and types.

My first-round interview for a Senior Software Engineer - Java role at EPAM took place in July 2024 and lasted 1.5 hours. The interview commenced with a basic introduction, then quickly transitioned into core Java features. There was a significant focus on streams, functional interfaces, and lambda expressions, and I was asked to solve 4-5 problems exclusively using Java streams. Following this, the interviewer delved into Java/JVM internals, garbage collection (GC), and the concept of immutable classes, grilling me thoroughly on these topics.

The latter part of the interview shifted to Data Structures and Algorithms (DSA). I was required to write and execute working code for two specific problems.

During my interview process at EPAM, I faced three distinct rounds. The first round was a Coding round focused on Core Java. I was asked to solve two main tasks. The first task involved filtering employees from a list based on their city ('Noida') and then sorting them in reverse alphabetical order by name, all while utilizing Java 8 Stream APIs. The second task presented two algorithmic problems: one was to find the product of all elements in an array except for the element at the current index, without using the division operator; the second was to merge k sorted linked lists into a single sorted list. I also encountered a couple of other questions on Java 8 features and stream APIs.

The second round was a HLD/Technical Round. Here, the discussion revolved around designing a high-level architecture for a food delivery application. Additionally, I was questioned on Java 8 features, various Design Patterns, SOLID principles, and Microservice Patterns.

Finally, the third round was the Managerial Round. This round primarily focused on my previous project experiences, followed by several behavioral questions. After completing all rounds, I received an offer for the Senior Software Engineer role.

I had my interview rounds at Epam Systems in Gurgaon. I have over 4 years of product experience and come from a Tier 2 college background.

Round 1 (1.5 hours) - Coding Round:
For this round, I was required to execute all my code on my local IDE. I was given three problems:
1. Finding the first repeating character in a given string like "asdfaghjklkjhgfdsa" using Java streams and lambda expressions. The expected output was 'a'.
2. Solving the 'Top view of a binary tree' problem.
3. Grouping anagrams from an array of strings, for example, ["eat","tea","tan","ate","nat","bat"] should output [["bat"],["nat","tan"],["ate","eat","tea"]].

Round 2 (1.5 hours) - Java Concepts & System Discussion:
This round focused on my knowledge of Java concepts and system design.
1. We discussed various Java 8 concepts, design patterns, SOLID principles, and threading classes in Java.
2. There were detailed discussions about my resume, specifically on projects where I had used Spring Boot, microservices, and Kafka.
3. I was given an easy design question: to design a service that would notify users on login/signup and credit them a point. I used draw.io to illustrate my design.

Round 3 (1 hour) - Managerial Round:
The final round was with a manager, primarily focused on my professional experience.
1. We talked about my projects and my contributions to them.
2. I was asked some basic Java questions.
3. I discussed my approach to designing systems while keeping SOLID principles in mind.
4. We also covered general behavioral questions.

My interview journey for the Junior Software Engineer role at Epam involved several rounds, ultimately leading to an offer. Here's a detailed breakdown of each stage:

Round 1: NCTE Test (MyAnatomy Platform)

The initial screening was conducted on the MyAnatomy platform, known as the NCTE test. This comprehensive assessment included sections on Aptitude, Analytical skills, English Proficiency, Computer Fundamentals, Coding Proficiency, and UI Technologies. Epam shortlisted candidates based on their scores from this round for subsequent stages.

Round 2: Coding Round

This round consisted of three coding challenges, which I had to solve using Java. The first question focused on Object-Oriented Programming (OOPs) concepts, where I was provided with an interface and several classes. My task was to implement the interface, extend classes appropriately, and fill in the logic for specific blank functions to solve the given problem. The second and third questions were medium-level problems related to Data Structures & Algorithms (DSA) and general problem-solving.

Round 3: Group Discussion

After a few days, I received an invitation for a Group Discussion round, which lasted 30 minutes. Approximately 10 candidates participated. The mentor began by introducing himself and providing a brief overview of Epam. The topic for discussion was "Who is more responsible for the second phase of Corona: the public or the government?" Despite limited time, I managed to contribute to the discussion once.

Round 4: Technical Interview

Following the GD, I was called for a 45-minute technical interview, which was primarily focused on Java. The questions covered a wide range of topics:

• I was asked to introduce myself.
• I had to explain all the questions I solved in the second coding round and elaborate on my logic.
• Discussions around OOPs concepts.
• Differences between LinkedList and ArrayList, specifically regarding insertion and deletion speed.
• Differences between Stack and Queue.
• Concepts related to static methods, static variables, and static blocks.
• Distinction between final, finally, and finalize.
• The size of long in Java.
• Binary Trees and Binary Search Trees (BST).
• Real-world applications of BSTs.
• Method Overriding.
• What is a Map in Java?
• Abstract classes versus Interfaces.
• What is the Collection framework?
• Can the main function be overloaded?
• Discussion about the Collections class.
• Defining various data structures within the Collection framework.
• I was asked to code a solution in Java to find a duplicate element in an array.
• A puzzle was presented: "You have two candles, both of which can burn for exactly 30 minutes each. You need to burn both candles for precisely 45 minutes."

Round 5: HR Interview

The final round was a 30-minute HR interview. This round focused on personal background, professional aspirations, and behavioral aspects:

• I was asked to tell about myself.
• Questions about my projects.
• Situational questions, such as describing a time I acted as a team player.
• Describing a situation where I made a mistake and how I handled it.
• Questions about my family background.
• Inquiries about my willingness to relocate.
• A hypothetical question: "If your parents advised against relocating, would you still be able to relocate?"
• Questions about my commitment duration to Epam.
• Another hypothetical: "If relatives suggested leaving Epam for a higher salary, what would I do?"
• My achievements.
• How I would manage a project with limited time.
• And some general discussion.

Several days after the HR interview, I received the confirmation email from Epam for the offer.