18 Java Design Pattern Questions for Interviews

Frequently asked Java design pattern questions from interviews

Hello guys, if you are preparing for Java interviews and looking for frequently asked design pattern interview questions then you have come to the right place.

In the past, I have shared Java Multithreading questions, Java Serialization questions, System Design interview questions and Enum Interview Questions and in this post, I am going to share popular design pattern questions from Java interviews.

You can use these questions to both practices and check your knowledge about OOP design patterns. Both OOP and GOF design pattern interview questions are an integral part of any good list of core Java interview questions.

Java is a popular Object-oriented programming language and has lots of design patterns and design principles, contributed by many developers and open-source frameworks.

As a Java developer, it's expected from you to know OOPS concepts like Abstraction, Encapsulation, and Polymorphism; what is a design pattern in Java, Some popular Java design patterns, and, most importantly, when to use those design patterns in Java application. 

The purpose of asking the design pattern interview question in Java is to check whether the Java programmer is familiar with those essential design patterns or not.

Design patterns in Java interviews are as crucial as multi-threading, collections, and programming questions and one should not neglect it. Good knowledge of Software design patterns goes a long way in becoming a better Java developer which every company looks for.

These Software design patterns provide templates and tricks used to design and solve real-world software problems and tasks. 

If you know how to apply and use these time-tested design patterns then you can write better code, I mean the code which is more inextensible, maintainable, and flexible.

If you are a senior or experienced Java programmer, then you can expect more complex and tough design patterns in Java interviews like Memento, Chain of Responsibility, and Builder design pattern and solving real-time software design questions.

By the way, always remember, giving an example from your project creates a better impression and if you want to learn about the modern implementation of design patterns in Java, I suggest you join the Design Patterns in Java course by Dmitri Nesteruk on Udemy.

In this course, you will not only learn how to recognize and apply design patterns but also how to Refactor existing designs to use design patterns

18 Java Design Pattern Questions and Answers

Here is my list of the top 18 design pattern interview questions in Java. I have also provided an answer to those Java design pattern questions as a link.

No matter which level of Java interview is you going like a programmer, software engineer, a senior software engineer in Java, you can expect a few questions from the Java design pattern.


1. What is the Decorator pattern in Java? Can you give an example of a Decorator pattern from JDK?