EPAM Java Developer Interview Experience 2026 | Real Questions + Coding Round

Añadido: 2026-05-13

[00:00:00]Hey everyone, recently one of our subscribers Vaishnavi cracked a Java backend developer interview at EPAM, okay? And she has shared her complete interview experience with me and I'll add her LinkedIn profile in the description, so you can confirm with her as well. And guys, along with the question, I'll give the answers just to give you the context, okay? So basically, she applied through LinkedIn and she has around 5.5 year of experience, okay? And guys, if you want to watch real interview experiences, then please make sure to subscribe. So now, let's get started. So guys, basically Vaishnavi told me that there were total three rounds. First was based on coding plus technical, second was pure technical, and third was techno-managerial, okay? So let's discuss each round one by one. So basically, in the first round, interviewer first started asking coding questions. First question was, you are given a sentence and you have to fetch the longest word in that sentence by using Java stream API, okay? For example, if the sentence is this is a stream problem. So here, problem is the longest word and you have to print that, okay? Second question was, you are given employee class which consists of name, age, salary, and department, okay? So you have to fetch all employees whose salary is greater than 50,000 by using stream API, okay? And guys, third question was that you have to write a JUnit test case of calculating prime numbers by using JUnit 5 and Mockito framework, right? And fourth question was to write basic CRUD REST API. So guys, these were the coding problems that were asked by interviewers. And I'll provide all the coding solutions and explanation in the description, otherwise video would be very longer, you know? Then guys, interviewer started asking some technical questions like what is garbage collection and its type.

[00:01:46]So basically guys, garbage collection is a feature in Java where JVM automatically cleans unused objects from memory, okay? So we don't have to manage it manually, right? It helps prevent memory leaks and keeps the app efficient. Are you getting my point? So basically, there are mainly three types.

[00:02:05]First, minor GC for new objects, second, major GC for old objects, and then full GC which cleans the entire memory, okay?

[00:02:14]Then interviewer asked difference between array list and linked list and their real time use case. So basically, array list works on dynamic arrays, so reading data is super fast, but inserting or deleting in between is slow. Whereas, linked list uses nodes, so insertions and deletions are faster, but accessing elements is slower, right?

[00:02:34]So in real projects, we should use array list for frequent reads like UI data and linked list for frequent updates like quiz or task processing. Are you getting my point?

[00:02:52]And guys, then interviewer asked what is polymorphism? So basically, polymorphism means one thing behaving in multiple ways, right? In Java, a method can perform different actions based on input or object type. So we have compile time polymorphism using method overloading and run time polymorphism using method overriding, right? It helps makes code flexible and reusable, which is very, very important in real world applications. Then interviewer asked what are bean scopes in Spring Boot? So basically, bean scope defines how many instance of a bean Spring will create and how long it lives, right? The default is singleton, meaning only one instance. Are you getting my point? Then we have prototype, request, session, and application scopes, okay? Depending on our use case like per user, per request, we choose the appropriate scope, right?

[00:03:48]And guys, before moving to the next question, I would like to share one important thing with you. Actually, Vaishnavi prepared from our interview preparation kit, so let me tell you this kit has four main parts. First is complete interview preparation material, right? It is a step-by-step material made by me, expert, and MNCs interviewers. 99% of the questions asked in interviews are covered in it, right?

[00:04:12]Second is two real enterprise client projects code and video recorded sessions are there and you can add this in your resume. Third is lifetime chat support. Here you can ask your doubts anytime and fourth is referral support.

[00:04:25]Here we help you to get referred to the top MNCs, okay? So basically, the material is organized as per your experience level and covers Java, Spring Boot, Spring Security, Spring Data JPA, microservices, Kafka, Maven, Git, coding questions, stream API coding questions, and many more. You can buy just the complete interview preparation material or the full interview preparation kit with project supports and referrals, okay? I have added the links in the description below, so now moving to our interview experience. Guys, then interviewer asked how would you implement exception handling globally in Spring Boot, right?

[00:05:00]So basically, instead of writing try-catch everywhere, we use controller advice with exceptional handler annotation to handle the exceptions in one place, you know? We just create a global class, define methods for specific exceptions, and return proper responses, right? And you know, this keeps the code clean and makes error handling consistent across the entire application. Are you getting my point?

[00:05:25]So guys, this was the first round and in the second round, interviewer first spent some time understanding her background, the projects she worked on, and the technologies she used. Then interviewer asked, "Can you please explain internal hash map?" Okay? So basically, hash map stores data in key-value pairs using an array of buckets. When we put a key, it basically calculates a hash code to find the index. If multiple keys lands on the same index, collision happens, right?

[00:05:55]And they are stored using linked lists or tree. During get method, it again calculates hash and searches in that bucket. Guys, then interviewer asked, "Why we switched from linked list to red-black tree in case of hash collision from Java 8?" So basically, earlier collision were handled using linked list, as we know, which could become slow like O(n) if many elements land in the same bucket, right? But in Java 8, after a threshold, it converts into arbitrary, making search faster. Now it will be O(log n). This improves performance and avoids worst-case scenarios, okay? Then guys, interviewer asked, "What is circular dependency and how would you fix it?" So basically, circular dependencies happens when two beans dependent on each other directly or indirectly like A depends on B and B depends on A, okay? This causes issues in bean creation and we can fix it by using lazy annotation, setter injection instead of constructor injection, or redesigning the logic to break the dependency. Then interviewer asked, "What is transactional annotation?" So guys, basically, transactional annotation is used to manage database transaction in Spring, as we know, right? It ensures that a set of operations either complete fully or roll back completely if any errors occurs, right? It basically helps maintain data consistency. We can also control propagations, isolation, and rollback rules by using its properties, right? Then interviewer asked, "How would you secure your REST API?" So basically, we secure our REST API by using Spring Security. Common methods are authentications like JWT or OAuth2, authorizations like role-based access, HTTP encryptions, input validations, and rate limiting, right? JWT is widely used where a token is generated after login and sent in headers for every request to validate the users. Are you getting my point? Then interviewer asked, "What is value annotation?" So guys, basically, value annotation is used in Spring to inject values into variables from properties files, environment variables, or expressions, right? For example, we can fetch values from application.properties like database URL or API keys, right? It helps in externalizing configuration and makes application flexible, okay?

[00:08:15]Then interviewer asked, "What does embedded ID annotation do?" So basically, embedded ID annotation is used in JPA when we have composite primary key. Instead of multiple ID annotation fields, we create a separate class containing all key fields and embed it into the entity, right? It helps keep the code clean and manages complex primary keys in a structured way. Then interviewer asked, "Could you please explain about facade design pattern?" So basically guys, facade design patterns provides a simple interface to complex system, right?

[00:08:49]Instead of calling multiple classes or APIs, we create one facade class that handles everything internally. It hides complexity and makes the code easy to use. In real projects, it's used when integrating multiple services or modules behind one clean API. Are you getting my point? Guys, then interviewer asked, "What is circuit breaker pattern?" So very simple question. So basically, circuit breaker pattern is used to handle failures in microservices, right?

[00:09:16]If a service is down or slow, the circuit opens and stops further calls, preventing overload, right? After some time, it tries again and it improves the system resilience and avoids cascading failures, right? Tools like Resilience4j are commonly used here. Guys, then interviewer asked, "How would you achieve centralized logging mechanism in microservices architecture?" So basically, in microservice, we use centralized logging by sending logs from all services to one place like ELK stack, Elasticsearch, Logstash, Kibana, right? Each service pushes logs and we can search and monitor everything in one dashboard. Basically distributed transaction in microservice architecture?" Okay? So, basically, distributed transactions are handled using pattern like Saga or two-phase commit. Are you getting my point? In microservices, Saga is preferred because it avoids locking and improves scalability. Each service performs its transaction, and if something fails, compensating actions are triggered to roll back previous steps.

[00:10:25]Then interviewer asked, "What is Saga pattern?" So, basically, guys, Saga pattern is used to manage transactions across multiple services, right? Instead of one big transaction, it breaks it into the smaller steps. Each service completes its part, and if any step fails, previous steps are undone using compensating transactions. It ensures data consistency without using heavy locking. Okay? Then interviewer asked difference between Kafka and Q. So, basically, guys, Kafka is distributed event streaming platform where data is stored and can be consumed multiple times. Whereas, Q like RabbitMQ removes the message once consumed. Are you getting my point? Kafka is used for high-throughput real-time data streaming, while queues are used for task processing and decoupling services.

[00:11:15]And Kafka supports replay. Queues generally don't support replays. Okay?

[00:11:21]Guys, then interviewer asked, "What is query planning?" So, basically, query planning is how a database decides the best way to execute a query. Okay? It checks different possible approaches like index, joins, and scanning methods, and then choose the most efficient one.

[00:11:37]Right? This basically improves performance and reduce execution time.

[00:11:41]And tools like query execution plans helps developers understand and optimize queries. Then guys, interviewer asked, "Explain SOLID principle." So, basically, SOLID principle is a set of five principles to write clean and maintainable code. Right? S is single responsibility, O is open-closed, L is Liskov substitution, I is interface segregation, and D is dependency inversion.

[00:12:04]This principle helps in writing flexible, scalable, and loosely coupled code, right? And this is very, very important in real-world applications.

[00:12:11]So, we have to follow the SOLID principles, right? Then interviewer asked to explain the ACID properties.

[00:12:16]So, basically, ACID ensures reliable data transaction. A is atomicity, means all or nothing, right? C is consistency, means valid data. I is isolation, means transactions don't interfere, right? And D is durability, means data is saved permanently. These properties ensure that even in failure cases, the database remains correct and stable. Okay? Then interviewer asked that you are given a singleton instance class and asked candidates to implement lazy initialization, right? So, basically, lazy initialization means creating the object only when it is needed, as we know, right? In singleton, we keep the instance null initially and create it inside get instance method when first called, right? This saves memory and improves performance. For thread safety, we can use synchronized block or double-checked locking. Are you getting my point? Then interviewer asked fail-fast and fail-safe iterators. So, basically, fail-fast iterators throws an exception. Uh we can say concurrent modification exception, right? If the collection is modified while iterating, we usually get this error. Examples are array list and hash map. Okay? Fail-safe iterators don't throw exceptions and work on a copy of the collection like in concurrent hash map. Fail-fast is faster, while fail-safe is safe for concurrent environments. Okay? So, guys, this was a second round, and in the third round, interviewer asked some managerial questions like, "Why would you want to join us? What's the most challenging task you have faced in your last project? Did you face any conflicts with your teammates? Etc., etc., right?"

[00:13:53]So, guys, this is all about Vaishnavi technical interview experiences at EPAM.

[00:13:57]And if you want to watch more interview experiences, then please make sure to like and subscribe. Thank you. Bye-bye.