The first release candidate of Spring 2.5, formerly known as version 2.1, was recently released. InfoQ spoke with Spring framework lead developer Juergen Hoeller to learn more about this release.
Hoeller told InfoQ that the final release of Spring 2.5 is currently scheduled for November 19th. The major features of this release are:
- Seamless upgrade from Spring 2.0 - Spring 2.5 is designed to be a drop-in upgrade for Spring 2.0, no changes should be required to code or configuration
- More XML configuration namespaces - New namespaces include
<jms> and <context> - Full Java 6 and Java EE 5 support - All of the new features in Java 6 and Java EE 5 are fully supported by Spring - full support is also maintained for Java 1.4.2 and J2EE 1.3
- Full annotation-based configuration support - All configuration can now be done using annotations, and JSR 250 annotations are also supported
- Annotation-based MVC controller - Web Controllers can now be created with annotations such as @RequestMapping, and no interface has to be implemented
- AspectJ support - support for AspectJ load-time weaving has been added for some environments, there is also a new bean() pointcut
- OSGi support - All of the 2.5 framework JARs are OSGi-compliant bundles to easae usage in OSGi environments
- Completely revised test context framework - TestNG and JUnit 4 tests are now supported by the new annotation-based test context framework
- Performance improvements - There have been significant improvements in all aspects of Spring's performance
A comprehensive changelog is also available.
With Spring 2.5 nearing release, some people have compared it's performance to Google's Guice framework. Solomon Duskis compared the performance of Spring against Guice, and determined that Spring 2.5 was 200% faster than 2.0 for concurrent access, and faster than Guice when changing the default bean instantiation behaviour to singleton. Duskis also created a Guice-style Spring 2.5 application, and discussed his experience in detail. William Louth expanded upon this by doing a detailed comparison of Guice and Spring under several different configurations including concurrent access and singleton factory. Louth's analysis reveals that, in some configurations, Spring 2.5 is now faster than Guice, and overall the two frameworks are now much closer in performance.
Hoeller also discussed the plans for Spring 3.0 - a 2.6 release has been dropped, and 3.0 will be the next major release. The first milestone is expected to be available in May 2008, with a final release targeted for October 2008. The mimimum requirements will be Java 5 and J2EE 1.4, and Java 7 support is also possible. For Java 5 usage of Spring 2.5, the transition to Spring 3.0 should be seamless - however, older features such as Commons Attributes will be dropped since they are no longer relevant to Java 5. Spring 3.0 will also be repackaged, with possible inclusion of the Spring Web Services/OXM package and the binding/expression language package from Spring Web Flow in the core framework.
