Java Interview Prep

A comprehensive collection of Java interview questions ranging from core fundamentals to advanced topics like concurrency, JVM internals, and Spring Boot.

Topics covered:

  • Core basics (JDK vs JRE, String pool, exceptions, autoboxing, pass-by-value, static)
  • OOP principles (inheritance, polymorphism, abstract vs interface, composition, encapsulation, nested classes)
  • Collections framework (List, Set, Map, HashMap internals, ArrayList vs LinkedList, fail-fast)
  • Concurrency & multithreading (synchronized, volatile, executors, CompletableFuture, ThreadLocal, Locks)
  • JVM internals (memory model, garbage collection, class loading, JIT compiler)
  • Streams & functional Java (lambdas, Stream API, Optional, Collectors, parallel streams)
  • Spring Boot essentials (IoC/DI, beans, transactions, starters, auto-config, profiles, actuator, REST, exception handling, JPA, security, caching, async/scheduled, testing, AOP)
  • Advanced (generics, serialization, design patterns, reflection, annotations)