spring-core (Spring core module): This contains the core components of the framework which includes the Inverse of Control principle and Dependency Injection (DI).

spring-beans (Spring bean module): This contains the bean generation using BeanFactory and fetches injected beans using the method getBean().

spring-context (Spring context module): Built by the core and bean modules that provide the interfaces of ApplicationContext with some features like resource bundling, internationalization, and scheduling.

spring-context-support (Spring context support module): This module contains the classes needed for integrating third-party applications to a Spring Application Context.

spring-web: This contains the web features of the Spring Framework which includes the initialization of the IoC container using servlet listeners and a web-oriented application context.

spring-webmvc (Spring MVC module): This is the module that has the MVC implementations and features.

spring-tx (Spring Transaction module): This contains transaction management on Bean object declarations with some special interfaces for all the POJO objects.

servlet-api: This contains all the classes and interfaces that describe the interaction between a servlet class and the runtime environment provided for the instance of a class within the bound of the servlet container.

jsp-api: This contains all the classes that implement the JspPage interface.

jstl: This contains all the classes and interfaces for Taglib support for all JSP pages.

javax-mail: This provides a platform-independent and protocol-independent framework to build mail and messaging applications.

javax.validation: This provides JSR-303 annotations for Java Bean validation.