Spring Framework

The Spring website (https://projects.spring.io/spring-framework/) defines Spring Framework as follows: The Spring Framework provides a comprehensive programming and configuration model for modern Java-based enterprise applications.

Spring Framework is used to wire enterprise Java applications. The main aim of Spring Framework is to take care of all the technical plumbing that is needed in order to connect the different parts of an application. This allows programmers to focus on the crux of their jobs--writing business logic.

Problems with EJB

Spring Framework was released in March 2004. When the first version of Spring Framework was released, the popular way of developing an enterprise application was using Enterprise Java Beans (EJB) 2.1.

Developing and deploying EJBs was a cumbersome process. While EJBs made the distribution of components easier, developing, unit testing, and deploying them was not easy. The initial versions of EJBs (1.0, 2.0, 2.1) had a complex Application Programmer Interface (API), leading to a perception (and truth in most applications) that the complexity introduced far outweighed the benefits:

• Difficult to unit test. Actually, difficult to test outside the EJB Container.
• Multiple interfaces need to be implemented with a number of unnecessary methods.
• Cumbersome and tedious exception handling.
• Inconvenient deployment descriptors.

Spring Framework was introduced as a lightweight framework aimed at making developing Java EE applications simpler.