Singleton in Spring Framework (Explained in Easy way!)

Spring is a very powerful framework for creating enterprise and distributed web applications. It is the most popular frame work used in the industry and the demand for it is ever growing.
Spring offers many features like dependency injection, aspect oriented programming, separation of concerns, and a host of other features. But the core functionality of a spring application is offered by spring beans.
To the most port, spring beans are singleton in nature and learning about singleton beans in spring would lay a solid foundation for learning rest of the spring framework.