Nextiva Junior Java Developer interview questions

🧠 The process included 3 technical rounds (excluding HR) — all focused on Java, DSA, system design fundamentals, and real-time problem-solving. 🔹 Round 1 – Core Java + DSA + SQL DSA Problem: Find the maximum product of a triplet in an array 👉 Input: 1, 4, 7, 9, -2, 10 → Output: 630 👉 Input: -4, -5, 0, 2, 3, 9 → Output: 180 Java Questions: 👉 What is the Collection Framework in Java? 👉 Difference between List, Set, and Queue 👉 JVM vs JRE vs JDK 👉 Java 8 features (Lambda Expressions, Default & Static methods, etc.) 👉 Code Binary Search + Time Complexity SQL: Write a query to fetch the 3rd highest salary from an Employee table. 🔹 Round 2 – DSA + Java Internals + Culture Fit LeetCode Problems: 1. Longest Substring Without Repeating Characters – also asked to print it and analyze time complexity. 2. Balanced Parentheses – Solved with a space-optimized approach (without using stack). Interviewer appreciated the use of O(1) space. Java Questions: 👉 Iterable vs Collection interfaces 👉 How HashMap works (Asked again) 👉 Multithreading concepts 👉 Memory Management and Garbage Collector in Java Also discussed some Linux commands and had a light conversation about my college life in NIT Agartala, the culture of Tripura, and local languages. 🔹 Round 3 – Managerial + Conceptual Discussion Coding: Write code for generating the Fibonacci Series 👉 Java OOPs Concepts: 👉 Constructor vs Interface 👉ArrayList vs LinkedList Other Topics: 👉 Basics of REST API 👉 Introduction to Spring Boot 👉 Real-world backend scenarios 👉 Role expectations and cultural questions 💬 Overall, the experience was enriching. The interviewers were friendly and genuinely curious about both my technical skills and personality. 💡 Advice to fellow developers preparing for backend interviews: 👉 Master core Java + OOPs + Java 8 features 👉 Practice DSA (LeetCode/Easy–Medium level) 👉 Be ready to explain your approach, optimize, and discuss trade-offs 👉 Understand Collection Framework, Multithreading, and Memory Management 👉 Revisit SQL basics and REST API fundamentals