If you have been using the Spring Framework for some time, you will be aware that Spring has undergone two major revisions: Spring 2.0, released in October 2006, and Spring 2.5, released in November 2007. It is now time for a third overhaul resulting in Spring 3.0. The Spring Framework is now based on Java 5 and Java 6 is fully supported. Furthermore, Spring is compatible with J2EE 1.4 and Java EE 5, while at the same time introducing some early support for Java EE 6.

The entire framework code has been revised to take advantage of Java 5 features like generics, varargs and other language improvements. We have done our best to still keep the code backwards compatible. We now have consistent use of generic Collections and Maps, consistent use of generified FactoryBeans, and also consistent resolution of bridge methods in the Spring AOP API. Generified ApplicationListeners automatically receive specific event types only. All callback interfaces such as TransactionCallback and HibernateCallback declare a generic result value now. Overall, the Spring core codebase is now freshly revised and optimized for Java 5. Spring's TaskExecutor abstraction has been updated for close integration with Java 5's java.util.concurrent facilities. We provide first-class support for Callables and Futures now, as well as ExecutorService adapters, ThreadFactory integration, etc. This has been aligned with JSR-236 (Concurrency Utilities for Java EE 6) as far as possible. Furthermore, we provide support for asynchronous method invocations through the use of the new @Async annotation (or EJB 3.1's @Asynchronous annotation).

The current documentation is a *** WORK IN PROGRESS *** and is currently being re-written to reflect all the changes in the framework and from now relying on Java 5 features. The Spring reference documentation has also substantially been updated to reflect all of the changes and new features for Spring 3.0. While every effort has been made to ensure that there are no errors in this documentation, some errors may nevertheless have crept in. If you do spot any typos or even more serious errors, and you can spare a few cycles during lunch, please do bring the error to the attention of the Spring team by raising an issue.

The framework modules have been revised and are now managed separately with one source-tree per module jar: org.springframework.aop org.springframework.beans org.springframework.context org.springframework.context.support org.springframework.expression org.springframework.instrument org.springframework.jdbc org.springframework.jms org.springframework.orm org.springframework.oxm org.springframework.test org.springframework.transaction org.springframework.web org.springframework.web.portlet org.springframework.web.servlet The spring.jar artifact that contained almost the entire framework is no longer provided. We are now using a new Spring build system as known from Spring Web Flow 2.0. This gives us: Ivy-based "Spring Build" system consistent deployment procedure consistent dependency management consistent generation of OSGi manifests

This is a list of new features for Spring 3.0. We will cover these features in more detail in the following sections. Spring Expression Language IoC enhancements Comprehensive REST support @MVC additions Declarative model validation Early support for Java EE 6

Spring introduces an expression language which is similar to Unified EL in its syntax but offers significantly more features. The expression language can be used when defining XML and Annotation based bean definitions and also serves as the foundation for expression language support across the Spring portfolio. Details of this new functionality can be found in the chapter Spring Expression Language (SpEL).

Core JavaConfigfeatures added

Work in progress

Work in progress

Work in progress

Hibernate Validator, JSR 303

JSF 2.0, JPA 2.0, etc