Iris Java Developer Interview Subtitles & Questions Download

Hey everyone, recently one of our subscribers Krishna Kumar cracked Java developer interview at Iris software. He has shared everything with me. So basically he had applied through Iris website and he's having total 3 years of experience. I'll be sharing his technical round experience only guys and if you want to share your interview experience then fill the form below in the description and please make sure to subscribe to see such real interview experience. So now let's get started. First interview asked to explain your current project flow from API request to database. What part of the systems do you own completely? What was the last production bug you fixed and how did you debug it? What design decisions in your project didn't scale well initially. So guys you have to answer these type of question as per your experience level. Then he asked to give a real example where inheritance cause problem. So giving you as per of my project experience we had a base user class and many subasses like admin user and customer user later a small change in base user validation broke multiple child classes unexpectedly. It creates tight coupling made debugging hard and forced changes across many modules at the same time. Then interviewer asks where did you use composition and why? So you can say in my project I use composition by building services using a smaller components like order service using payment service and notification service. Instead of extending classes I injected dependencies. This made the code loosely coupled easy to test and flexible because uh we could replace or modify one component without affecting the whole design. Then they ask how did our wrong equals and hash code implementation break something. So you can say we use a user object as a key in a hashmap but equals compared user ID while hash code use name. Because of this mismatch the same user got stored as multiple keys and lookup failed. It caused duplicate caches entries and incorrect data being returned. Then interviewer asked why did you avoid using oop and keep things simple. So you can say in my project I avoided heavy oops when the requirement was simple like converting a request to a response or doing a small validations. Instead of creating many classes and abstractions I use simple utility methods and clear details. It reduced complexity and improved readability. Then interviewer asked why did you choose map instead of list in one real scenario. So you can say in one of the module I needed to fetch customer details quickly using customer ID. If I used a list, I would have to loop every time to find the match. So I use a map with a customer ID as the key which give fast open lookup and improve the performance. Then interviewer asked when did hashmap become a performance issue. So hashmap becomes a performance issue when your operations stop being average and start degrading usually due to many collisions. This happens with a bad hash code, weak key distribution or an undersize mapped with frequent rehashing. Then lookups drift toward on and latency spikes. Then interview asked, "Have you ever replaced one collection with another for optimization?" So you could say yes when profiling showed the collection choice was the bottleneck. For example, I replaced an array list with an link list for heavy middle insertions and swapped a hashmap for an enum map when keys were enums. The goal was fewer allocations, faster lookups and predictable performance. And before moving to the next question guys, I would like to share one important thing with you. Actually Krishna prepared from our interview preparation kit. So let me tell you this kit has four main parts. First is complete interview preparation material. It is a step-by-step material made by me expert and MNC's interviews. 99% of the questions asked in interviews are covered in it. 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. Fourth is referral support. Here we help you get referred to the top MNC's. So basically the material is organized as per your experience level and covers Java, Spring Boot, Spring Security, Spring Data, JPA, microservices, Kafka, Maven, Gate 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. I have added the links in the description below. So now moving to our interview experience. Then interview asked to explain a bug caused by modifying a collection while iterating. So a common bug happens when we loop over a list with a for each and remove elements inside the loop. Java detects a structural change and throws concurrent modification exception. The correct approach is using an iterators remove method or collecting items to delete and removing them after iteration. Then they ask why did you need multi-threading in your project? So we need multi-threading to improve thoughtput and responsiveness. Some tasks like calling external APIs, processing files and generating reports were independent. By running them in parallel using thread pools, we reduce the waiting time, utilize CPU better and met latency SLAs under peak load. Then they ask what issue occur due to shared mutable data. So we face a raised condition because multiple threads updated the same mutable object without proper synchronization. Sometimes one threads over wrote another's changes. So counters were incorrect and data looked random. We fixed it by using immutability where possible and atomic classes or logs for shared state. Then interviewer asked why didn't synchronize solve the problems completely. So synchronize fixed correctness but it didn't fully solve performance and design issue. A single log become a bottleneck under load causing threads to block and latency to rise. Also syncing the wrong scope still allowed visibility issues elsewhere. We improved it with finer grain locks atomics and reducing shared state. Then they asked how did you decide the thread pool size? So we decided the thread pool size based on workload type and measured bottlenecks. For CPUbound task I keep it near the number of cores to avoid context switching. For input output bound task we allow more threads because they spend the time waiting. Then we validate with the load test and metrics. Then they ask where did streams make code worse instead of better. So streams made code worse when the logic needed complex branching early exist or detailed error handling. The stream pipeline become long and hard to debug and performance suffered due to extra allocations. In those cases, a simple loop was clearer, faster and easier to maintain. Then interviewer asked, "Have you faced performance issues with the streams?" So yes, you can say especially with large collections where a stream pipeline created many temporary objects and repeated boxing and unboxing. We also saw overhead from multiple intermediate operations like map, filter, and collect. After profiling, we replace hot paths with plan loops or optimized collections and got better latency. Then interviewer asked when did optional create confusion. So optional created confusions when developers treated it like a normal field type and started passing optional everywhere even storing it in entities that made an API noisy and hide real nullability rules. We teach using optional mainly for return values not parameters and never for persistence models. Then they ask how did you use completable future in real flow. So you can say I use completable future to run independent task in parallel like fetching user details, order history and recommendations from different services. Then I combined results by using all of and then combine method handled failures with exceptionally method and returned a single aggregate response without blocking request threads. Then they ask how does spring boot simplify your daily work? So spring boot simplifies daily work by removing setup overhead. Auto configurations and starter gives us sensible default. So we focus on business logic instead of wiring means actuators helps with health checks and matrix and profiles makes environment config clean. Overall it speeds development and reduce production surprises. Then interviewer asked how do you handle global exceptions? So you can say we handle global exceptions by using controller advice with exceptional handler methods. This centralized errors responses keeps controller clean and ensures consistent HTTP status codes and messages. We also log with correlations ids map validations errors clearly and avoid leaking internal stack traces to clients. Then interviewer asks how do you validate request data properly. So we validate the request data by using bean validation annotations like not null size patterns on DTO's and trigger them with valid annotation in controller methods for cross field rules. We use a custom validators and we handle validation errors globally to return the clear consistent responses. Then interviewer asks how do you manage config differences across environment. So you could say we manage config differences using spring profiles and externalized configuration. Each environment get its own application profile version like ML and sensitive values come from environment variables or a secret manager. We also keep default safe use features flags when needed and verify config via actuator and startup checks. Then they ask what checks do you do before deploying code to the production. So before deploying to production we run a clear checklist. All units and integration test must pass. We review coverage for critical pass. We check static analysis and security scans. Validate configs for the target profile and confirm DB migrations are safe. Finally we do a smoke test with staging review logs metrics dashboards and ensures roll back is ready. And guys then interviewer asked two coding question. first to write the best way of singleton design pattern and then he asked to implement the caching by using map. So guys this is all about iOS software interview experience of Krishna. Please make sure to check the interview preparation kit. Thank you.