The Singleton design pattern is a commonly used design pattern in software engineering that ensures a class has only one instance and provides a global access point to obtain this instance. This pattern is often employed to control access to resources, such as reading configuration files or establishing database connections.
When implementing the Singleton pattern, the constructor is declared private to prevent other objects from creating instances with the new keyword. Additionally, the class provides a static method to create or return this unique instance. Since static methods can be invoked directly via the class name without creating an object instance, this ensures the class's global accessibility and uniqueness.