Design patterns often confuse developers during interviews, not because they don’t understand the definitions, but because they struggle with WHEN to use WHICH Design Pattern in real-life software design. This article gives scenario-based clarity on each pattern, making you interview-ready.

Understanding the definition of a design pattern is easy. Knowing when to use which design pattern is what makes you an architect. This article covers all 23 Gang of Four (GoF) patterns with practical usage, reasoning, and real-world scenarios that help developers answer tough interview questions. If you build Java apps (or any object-oriented systems), this article makes pattern selection easy. No more guesswork.