Design Pattern Interview Questions and Answers Introduction

Design patterns have become very popular interview questions, and in this section we present some of the design pattern questions being asked in interviews these days. What exactly are design patterns? Well, in software engineering there are design problems that commonly reappear in different projects. So, you can think of design patterns as guidelines to help you find a solution to some of those commonly reoccurring problems. Design patterns do not specify the actual code that needs to be used to solve a given problem, but just the guidelines.

Where did design patterns originate from?

Although design patterns were probably used by programmers for many years before, design patterns were formally introduced in computer science in a book called “Design Patterns: Elements of Reusable Object-Oriented Software”. This book was published in 1994 and is still considered to be the bible of design patterns. There are four people who wrote the book, and they are commonly referred to as the Gang of Four, or GoF (even Go4) for short – many times GoF is even used to refer to the book itself.

Design patterns versus frameworks

Are design patterns the same thing as frameworks? The answer to that is no. Design patterns are more like general guidelines on how to solve specific programming problems, but they do not specify the detailed code that’s necessary to solve those problems.

Why should we use design patterns?

Design patterns are useful because they provide a pre-formulated solution to problems based on the experience of other programmers. This can save you a lot of time.

Design patterns also help in communication of a programming solution, and provide a common technical vocabulary between programmers.

What about anti-patterns?

Of course, using the wrong design pattern can have a very negative effect on your code. So, it takes good judgement to use the correct design pattern. The term “anti-pattern” is used to describe a poor programming practice that leads to ineffective code.

Interview questions about design patterns are becoming more popular, especially for more mid to senior level programming jobs. You can get started on reading our set of questions by clicking Next, or clicking the page of interest on the left in the menu bar.

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