Spring framework is lightweight when it comes to size and transparency. The basic version of spring framework is only 2MB. It was first written by Rod Johnson and was released in June 2003 under the Apache 2.0 license. If you want to extend your code that was written using spring framework or setting out to write a new one, a good knowledge of Spring Core is very important.
Spring framework is also a complete ecosystem of supporting tools that provide you everything client need to build applications. It is helpful for both beginners and experienced persons. The spring framework comprises several modules such as IOC, DAO, Context, AOP, ORM, and WEB MVC. It also provides support to various frameworks such as Struts, Hibernate, Tapestry, EJB, JSF etc.
Spring enables developers to develop enterprise-class applications. Because environment dependent code is moved into this framework very easily, testing an application written with spring is very simple. Spring is organized in a modular form. Spring provides a consistent transaction management which can scale down both local transaction and global transactions. Learn the magic of Spring Framework in 90-100 Steps with Webomind.