What is Singleton design pattern? Of the Gang of Four design patterns, Singleton is the Creational design pattern used while creation of the object of the class. The creational design pattern is a technique to ensure that there is strictly only one instance of a particular class in your program. Why Singleton? Suppose that your classes are using external resources like a database server, or a web Api etc, it would be a real problem if multiple objects try to use those resources at the same time. In such cases, singleton design pattern can help in overcoming the drawback in the above scenarios. Real world example with code Suppose your program need to log the changes made in some data into a log file. Generally, in absence of the pattern, multip le objects may try to access the same log file which could create conflict. With a singleton log class object, you don't need to worry about several different objects trying to access the sa...