Describe the Singleton design pattern.

Describe the Singleton design pattern.

The Singleton design pattern is a creational design pattern that restricts the instantiation of a class to a single object. It ensures that only one instance of the class exists throughout the application and provides a global point of access to this instance. The Singleton pattern is commonly used when there is a need for a single, shared resource or when it is necessary to control the number of instances of a class. It is implemented by creating a private constructor, a static method to access the instance, and a static variable to hold the single instance of the class.