Who's using Spring?

There are many production applications using Spring. Users include investment and retail banking organizations, well-known dotcoms, global consultancies, academic institutions, government departments, defence contractors, several airlines, and scientific research organizations (including CERN).

Many users use all parts of Spring, but some use components in isolation. For example, a number of users begin by using our JDBC or other data access functionality.

Since the first version of this article, in October 2003, Spring has progressed through its 1.0 final release (March 2004) through version 1.l (September 2004) to 1.2 final (May 2005). We believe in a philosophy of "release early, release often," so maintenance releases and minor enhancements are typically released every 4-6 weeks.

Since that time enhancements include:

• The introduction of a remoting framework supporting multiple protocols including RMI and various web services protocols
• Support for Method Injection and other IoC container enhancements such as the ability to manage objects obtained from calls to static or instance factory methods
• Integration with more data access technologies, including TopLink and Hibernate 3 as well as Hibernate 2 in the recent 1.2 release
• Support for declarative transaction management configured by Java 5.0 annotations (1.2), eliminating the need for XML metadata to identify transactional methods
• Support for JMX management of Spring-managed objects (1.2).
• Integration with Jasper Reports, the Quartz scheduler and AspectJ
• Integration with JSF as a web layer technology

We intend to continue with rapid innovation and enhancement. The next major release will be 1.3 (final release expected Q3, 2005). Planned enhancements include:

• XML configuration enhancements (planned for release 1.3), which will allow custom XML tags to extend the basic Spring configuration format by defining one or more objects in a single, validated tag. This not only has the potential to simplify typical configurations significantly and reduce configuration errors, but will be ideal for developers of third-party products that are based on Spring.
• Integration of Spring Web Flow into the Spring core (planned for release 1.3)
• Support for dynamic reconfiguration of running applications
• Support for the writing of application objects in languages other than Java, such as Groovy, Jython or other scripting languages running on the Java platform. Such objects will benefit from the full services of the Spring IoC container and will allow dynamic reloading when the script changes, without affecting objects that were given references to them by the IoC container.

As an agile project, Spring is primarily driven by user requirements. So we don't develop features that no one has a use for, and we listen carefully to our user community.

Spring Modules is an associated project, led by Rob Harrop of Interface21, which extends the reach of the Spring platform to areas that are not necessarily integral to the Spring core, while still valuable to many users. This project also serves as an incubator, so some of this functionality will probably eventually migrate into the Spring core. Spring Modules presently includes areas such as integration with the Lucene search engine and OSWorkflow workflow engine, a declarative, AOP-based caching solution, and integration with the Commons Validator framework.

Interestingly, although the first version of this article was published six months before the release of Spring 1.0 final, almost all the code and configuration examples would still work unchanged in today's 1.2 release. We are proud of our excellent record on backward compatibility. This demonstrates the ability of Dependency Injection and AOP to deliver a non-invasive API, and also indicates the seriousness with which we take our responsibility to the community to provide a stable framework to run vital applications.