Common problems where you should apply Singleton pattern

The Singleton pattern solves only one problem--if you have a resource that can only have a single instance, and you need to manage that single instance, then you need a singleton. Normally, if you want to create a database connection with the given configuration in the distributed and multithread environment, it might be the case that every thread can create a new database connection with a different configuration object, if you don't follow the singleton design. With the Singleton pattern, each thread gets the same database connection object with the same configuration object across the system. It is mostly used in multithreaded and database applications. It is used in logging, caching, thread pools, configuration settings, and so on.