Catalog of 22 classic design patterns, grouped by their intent.

Singleton pattern: Singleton pattern belongs to the creational pattern. It allows one instantiation or object for JVM Rules for singleton pattern: The constructor should be private. ​​private Singleton()

Today we will describe the first design pattern or rather anti-pattern, it is officially a design pattern, but for many it is also considered by me as anti-pattern, because it has many disadvantages that

A design theory proposes a hypothesis and provides criteria for evaluation, a design pattern is assumed to exist and to be perfect (perfection is the enemy of the good). A design theory seeks objective

Strategy: Defines a family of algorithms, encapsulates each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients who use it. Decorator: Attach additional