# Java Interview Questions Hello reader! The purpose of this article is to share some common java interview questions that I was asked in the past when going through job interviews with top financial firms. I hope that you'll find this useful. * What is a class? * What is an object? * Object VS class * Method overloading. * Method overriding. * Access modifiers (private, public, protected, default). * The difference between method overloading and method overriding. * Object-Oriented Programming: inheritance, polymorphism, abstraction and encapsulation. * Aggregation and association. * Dynamic binding (linked to abstraction). * Static keyword. * Final keyword. * Strings: discuss why they're immutable and what happens in the memory (stack and heap). The string is a class. * Stringbuilder VS Stringbuffer. * Interface: why it's used. * Can we have multiple inheritance? If not, why? What can we do instead? * Difference between abstract class and interface. * Memory management: garbage collection, the types of garbage collectors. * How does a hashmap work internally? * Collections Framework. * Exception handling: throw, throws keywords, what is a runtime exception. * Runtime Type Checking. * Difference between the keywords final, finally, finalize. * `try...catch` block. * Finally block. * Exception propagation. * Multithreading: what is a thread, how to create a thread (Runnable interface OR Thread class). * Thread safety. * Synchronize. * Difference between a set and a list. * Java 11 features. * JDK, JRE, JVM. * SOLID Principles. * Test-Driven Development. * Git commands. * What does "unboxing" mean? * Is Java "pass-by-value" or "pass-by-reference"? * How do you return multiple values in Java? * What does "covariance" mean? > **Related**: [Java Phone Interview Questions - Beginner Level](https://techwithmaddy.com/java-phone-interview-questions-beginner-level) Good luck! 🍀🍀🍀