by The singleton design pattern ensures that at any point of time a class has one and only one instance which can be accessed globally. This design pattern is useful in cases where exactly one instance is needed to co-ordinate between different modules of a software. Singleton design pattern can be used as a logger class or memory/thread pool classes for which only one instance of object is needed.
Static class
A Static class is a special type of class which can’t be instantiated and hence it can’t be inherited and it doesn’t allow overriding. Static class members can be directly accessed.
Differences between Singleton vs Static class
| Singleton Method | Static class |
|---|---|
| There can be only one instance of Singleton class. | Static class can’t be instantiated. |
| It can be inherited. | It can’t be inherited. |
| Singleton object can be passed as reference in functions. | It can’t be passed in function. |
| Singleton method provide flexibility for extension. | Static classes are very rigid and difficult to extend. |
| Interfaces can be implemented using Singleton method. | Interfaces can’t be designed using static classes. These are good to be used as Utility classes. |
| Singleton class can be lazy loaded whenever its needed. | Static classes are always loaded. |
