Lets you ensure that a class has only one instance, while providing a global access point to this instance.
- Add a private static field to the class for storing the singleton instance.
- Declare a public static creation method for getting the singleton instance.
- Implement "lazy initialization" inside the static method. It should create a new object on its first call and put it into the static field. The method should always return that instance on all subsequent calls.
- Make the constructor of the class private. The static method of the class will still be able to call the constructor, but not the other objects.
- Go over the client code and replace all direct calls to the singleton’s constructor with calls to its static creation method.
