When preparing for an interview for a software engineering position, you should always keep in mind that besides knowing the certain technology you are interviewing for, you should be well-prepared with some basic Object-Oriented programming theory.

Object-Oriented programming principles are the fundamental building block of every modern programming language or concept. The most widely used programming languages are Object-Oriented, including Java, Python, C#, C++ etc. They all implement the basic OOP principles, so when working with an Object-Oriented language, you should possess strong knowledge of the OOP basic theoretical principles.

When interviewing, your tech interviewer will most probably ask you a couple of basic OOP questions, in order to verify that you have the necessary fundamental knowledge and that you understand the principles of OOP, no matter what experience, or knowledge in a certain tech stack you have.

In this article, we are going to ask and answer 15 of the most important OOP interview questions to prepare you for your next interview.