This guide is for Indian job seekers preparing for Java backend roles, from freshers facing campus and first-job interviews to experienced developers moving into senior positions at product companies and IT services firms. It covers what interviewers ask most in 2025 and 2026 on Java 17 and 21 and Spring Boot 3: OOP, collections, equals and hashCode, streams, exceptions, concurrency and JVM memory, then dependency injection, auto-configuration, REST controllers, validation, JPA and Hibernate, security, microservices and testing. Questions are grouped as easy, medium and hard. Read each answer, compile the code yourself and practise explaining it aloud.
Questions you may be asked
What are the four pillars of OOP, with a Java example of each?
What is the difference between an abstract class and an interface in Java?
What is the difference between method overloading and method overriding?
What is the difference between == and equals() in Java?
