Spring provides a modular architecture that is one of the most important reasons for the popularity of the Spring Framework. Its layered architecture enables integration of other frameworks easily and without hassle. These modules provide everything that a developer may need to use in enterprise application development. The Spring Framework is organized into 20 different modules that are built on the top of its Core Container.

The following diagram illustrates different Spring modules organized in a layered architecture:

We will start with discussing the Core Container before moving on to other modules.