Everything a fresher or developer with up to two years of experience is asked in Java backend interviews: JVM basics, OOP, strings, collections, exceptions, multithreading basics, Java 8 streams, coding-round programs, Spring Core, Spring Boot, Spring MVC, Hibernate/JPA, SQL, microservices fundamentals, Maven and Git. Every question has a short answer to say first, the key points to cover, correct code where it helps, and the common trap to avoid.
Choosing collections, iterators, and how HashMap, HashSet and TreeMap work inside.
Threads, lifecycle, synchronization, volatile and the Java memory model at interview depth.
Functional interfaces, Java 8–21 features, and the Stream API coding questions every interview includes.
The classic Java programs asked in coding rounds, solved cleanly with complexity analysis.
IoC, dependency injection, beans, scopes, profiles and WebFlux vs MVC.
Auto-configuration, starters, runners, embedded servers, Actuator, testing and REST API design.
DispatcherServlet, request mapping, views, interceptors, exception handling, data binding and file uploads.
Sessions, entity states, caching, lazy loading, N+1, locking and real-world Hibernate scenarios.
Keys, joins, normalization, transactions, triggers, procedures, indexes and the SQL queries asked in interviews.
API gateways, communication, service discovery, consistency, deployment, monitoring, security and resilience.
Maven lifecycles, POM and dependencies; Git branching, merging, rebasing, stashing and undoing mistakes.
