Java Interview Questions and Answers Last Updated : 10 Dec, 2025 Comments Improve Suggest changes 259 Likes Like Report Java is the most used language in top companies such as Uber, Airbnb, Google, Netflix, Instagram, Spotify, Amazon, and many more because of its features and performance. In this article, we will provide 200+ Core Java Interview Questions tailored for both freshers and experienced professionals.Java Basics & Program FlowJava Core Concepts Object-Oriented Programming (OOP)Collections & Generics Advanced TopicsTo do well in interviews, you need to understand core syntax, OOP concepts, Collections Framework, memory handling and advanced features.1. Core Concepts:Variables & Data Types, Arrays, Strings & String Classes, Interfaces, Memory Model (Stack vs Heap), Garbage Collection, Shallow vs Deep Copy, Immutable Objects, Object-Oriented Programming (Classes, Objects, Inheritance, Polymorphism, Abstraction, Encapsulation).2. Advanced Topics:Exception Handling, Generics, Collections Framework, Multithreading, Lambda Expressions & Functional Interfaces, Streams API, Annotations, Reflection, Design Patterns (Singleton, Factory, Observer), Java 8+ Features. Create Quiz Comment A anshul_aggarwal Follow 259 Improve A anshul_aggarwal Follow 259 Improve Article Tags : Java Interview Questions interview-preparation Java-Interview Interview-Questions +1 More Explore Java BasicsIntroduction to Java3 min readJava Programming Basics9 min readJava Methods6 min readAccess Modifiers in Java4 min readArrays in Java7 min readJava Strings7 min readRegular Expressions in Java3 min readOOP & InterfacesClasses and Objects in Java5 min readAccess Modifiers in Java4 min readJava Constructors4 min readJava OOP(Object Oriented Programming) Concepts10 min readJava Packages2 min readJava Interface7 min readCollectionsCollections in Java12 min readCollections Class in Java13 min readCollection Interface in Java4 min readIterator in Java4 min readJava Comparator Interface5 min readException HandlingJava Exception Handling6 min readJava Try Catch Block4 min readJava final, finally and finalize4 min readChained Exceptions in Java3 min readNull Pointer Exception in Java5 min readException Handling with Method Overriding in Java4 min readJava AdvancedJava Multithreading Tutorial3 min readSynchronization in Java7 min readFile Handling in Java4 min readJava Method References7 min readJava 8 Stream Tutorial7 min readJava Networking6 min readJDBC Tutorial5 min readJava Memory Management3 min readGarbage Collection in Java6 min readMemory Leaks in Java3 min readPractice JavaJava Interview Questions and Answers1 min readJava Programs - Java Programming Examples7 min readJava Exercises - Basic to Advanced Java Practice Programs with Solutions5 min readJava Quiz1 min readJava Project Ideas For Beginners and Advanced15+ min read Like