Spring Framework Maven Artifacts

Engineering | Ben Hale | November 26, 2007 | ...

By popular demand, the Spring Framework Maven artifacts are now being uploaded to the Spring Snapshot Maven Repository. You can find details about all of the Spring Portfolio Maven repositories in my previous post but I'll reprint the details for the Spring snapshot repository here.

The Spring Snapshot Maven Repository is located at http://s3.amazonaws.com/maven.springframework.org/snapshot. Using this repository requires you to add an entry to the <repositories/> element in your POM. It should look like this:

    <name>Spring Portfolio Snapshot…

Spring Framework 2.5 Released

Releases | Juergen Hoeller | November 19, 2007 | ...

Dear Spring Community,
We are pleased to announce that the Spring Framework 2.5 final release is now available.

Spring 2.5 RC1 Released

Download | Support | Documentation | Changelog 

Spring 2.5 enhances Spring 2.0 with many exciting new features, including:

  • Full Java 6 and Java EE 5 support (JDBC 4.0, JTA 1.1, JavaMail 1.4, JAX-WS 2.0)
  • Full-featured annotation-driven dependency injection, including support for 'qualifiers'
  • Support for auto-detecting application components in the classpath and auto-configuring them as Spring managed objects
  • A new bean name pointcut element in AspectJ pointcut expressions
  • Built-in support for AspectJ load-time weaving based on the LoadTimeWeaver abstraction
  • New XML configuration namespaces "context" and "jms", for maximum convenience
  • A completely revised integration test framework, with first-class support for JUnit 4 and TestNG
  • A new annotation-based controller model for Spring MVC supporting Servlet and Portlet environments
  • Extended SimpleJdbcTemplate functionality, including support for named SQL parameters
  • Officially certified WebSphere support
  • The packaging of Spring Framework jars as OSGi-compliant bundles out of the box
  • The ability to deploy a Spring ApplicationContext as a JCA RAR file, for headless application modules
  • JCA 1.5 message endpoint management, for Spring-managed JMS and CCI message listeners

Check out the series What's New in Spring 2.5? for a walkthrough of the new Spring 2.5 features, including information on how to deploy the Spring sample applications that demonstrate them.

We recommend upgrading to Spring 2.5 from all previous Spring 2.0.x versions in order to benefit from the new features as well as the significant performance enhancements that Spring 2.5 has to offer. Spring 2.5 is designed as a drop-in replacement for Spring 2.0, except for the slightly restructured jar file contents (please see the readme file in the distribution for more information on this).

Please note that Spring 2.5 is still compatible with JDK 1.4.2+ and J2EE 1.3+. Java 1.4 users, for example on WebLogic 8.1 or WebSphere 5.1/6.0, are very welcome to upgrade to Spring 2.5 as well.  We recommend putting the backport-util-concurrent jar on the classpath when running on Java 1.4, which allows Spring and your applications to benefit from significant concurrency enhancements.

Enjoy Spring 2.5,

Juergen Hoeller
Lead, Spring Framework Development

Interface21 becomes SpringSource

Engineering | Rod Johnson | November 19, 2007 | ...

We're changing our name. This week, Interface21 will become SpringSource.

As we have built the company, Interface21 has earned a reputation for exceptional products, thought leadership, outstanding people, professionalism and top quality support and services. As we continue to deliver all of those things, we believe that changing our name will help our company bring them to a wider audience.

When I founded Interface21 in 2004, I had to pick a name. I believed Spring to be the future of enterprise Java, and "Interface21" reflected those feelings—the framework for the 21st Century. Now we’re…

The Spring Web Flow 2.0 Vision

Engineering | Keith Donald | November 15, 2007 | ...

Spring Web Flow 2.0 M2 has just released. I am particularly excited about this release because it sets the foundation we need to realize the bold vision we have for our community for the future. In this entry, I'll explain what that vision is, and exactly what this foundation will enable. I'll also go into detail about the architecture of Web Flow 2.0, and compare it to the 1.0 version.

The Spring Web Flow 2.0 Vision

The goal of 2.0 is to evolve Spring Web Flow as a controlled navigation engine to offer significantly improved support for JavaServerFaces, flow managed persistence, and asynchronous event handling (Ajax) natively. The new Spring Faces project will build on Web Flow 2.0 to provide first-class support for JSF views in a Spring environment. In addition, Web Flow will continue to provide first-class support for Spring MVC-based views, allowing native JSF and MVC views to be used to full-power, even in the same application if desired.

* UPDATE: The vision above was updated on 1/11/08 after considering large amounts of feedback from the Spring community since The Spring Experience 2007. Based on that feedback, Spring Web Flow 2.…

Annotated Web MVC Controllers in Spring 2.5

Engineering | Juergen Hoeller | November 14, 2007 | ...

Spring 2.5 introduces an approach for writing annotated Web MVC controllers, which we haven't been blogging about much yet... I'll take the opportunity to give you an overview of what Spring MVC is really about these days.

Spring MVC is essentially a request dispatcher framework, with a Servlet API variant and Portlet API variant. It operates very closely within its hosting environment - either Servlets or Portlets. Think about Spring MVC as providing foundational facilities and conveniences on top of the Servlet/Portlet container: e.g. flexible request mappings, separation between controller…

Download the \"Spring in Production\" white paper

Engineering | Adrian Colyer | November 09, 2007 | ...

We recently hosted a webinar on the theme of "Spring in Production." I promised then to make the recording of the webinar and accompanying slides available on our website. Unfortunately the engineers producing the webinar for us forgot to set the 'record' flag, so I need to re-record the session for you :(. I'm traveling at the moment but I'll try to do that and make it available as soon as I can.

The good news is that there's no need for you to miss out in the meantime. I wrote a white paper on the topic of "Spring in Production" that covers the material from the webinar and more besides…

A Response to: EJB 3 and Spring Comparative Analysis

Engineering | Mark Fisher | November 09, 2007 | ...

Last night I attended a New England Java User Group (NEJUG) meeting where Reza Rahman presented a "comparative analysis" of EJB 3 and Spring. Reza is one of the authors of EJB 3 in Action. I enjoyed meeting Reza and respect him for presenting what may be considered a controversial topic. Also I appreciate that he did attempt to address pros and cons for both EJB 3 and Spring. Nevertheless, I feel compelled to clarify a few points that were not wholly accurate in his coverage of Spring and which led me (and other attendees) to believe the presentation was motivated by a bias toward EJB 3. To be fair, unlike a fixed specification version, Spring is constantly evolving and some of the things that I will point out here are new features. On the other hand, some are Spring 2.0 features that have been available for more than a year. I personally believe that a "comparative analysis" must account for the up-to-date feature set of the latest stable version of the products being compared. I think it goes without saying that I might be a bit biased as well, but my motivation here is to provide a wholly objective response so that the presentation could perhaps be revised to reflect a more 'apples-to-apples' comparison. I will provide brief responses to 10 "themes" of the presentation.

1. EJB uses annotations for metadata. Spring uses XML.

It was mentioned that Spring is beginning to support more annotations but that it is "going to take them a while". However, the Spring 2.0 release provided full JPA integration with @PersistenceContext for injecting the EntityManager and annotation-driven transaction management with Spring's @Transactional annotation (supporting the same semantics as a @Stateless EJB with the default propagation of REQUIRED). I was particularly discouraged that the comparison did not include JPA on both sides (see point #3 below). Spring 2.0 also introduced full annotation-based AspectJ support (@Aspect, @Before, @After, @Around) and the concept of "stereotype" annotations. For example, the @Repository annotation enables non-invasive Exception translation for data-access code that uses JPA or Hibernate APIs directly (without Spring's templates). Spring even provided annotation support as early as version 1.2, such as @ManagedResource for transparently exporting any Spring-managed object as a JMX MBean.

Now the main reason this issue is #1 for me, is the comment that it is "going to take them a while". As one of the main developers of Spring 2.5's annotation-driven configuration support, I must say that the Spring metadata model is extremely flexible and therefore we have been able to provide a comprehensive annotation-based model more quickly than one might expect. In fact, Spring 2.5 provides support for JSR-250 annotations: @Resource, @PostConstruct, and @PreDestroy - as well as @WebServiceRef and @EJB. Of particular interest is @Resource since it is the primary annotation used for dependency injection in EJB 3. With Spring, the @Resource annotation supports not only JNDI lookups (as with EJB 3) but also injection of any Spring-managed object. This effectively combines the main Spring advantage that was mentioned in this presentation (Spring supports DI of any type of object) with the main EJB 3 advantage (use of annotations instead of XML). Spring 2.5 also introduces an even more fine-grained annotation-driven dependency injection model based on @Autowired and the (extensible) @Qualifier annotation. Spring 2.5 also extends the "stereotype" annotations to include @Service and @Controller. Each of the stereotype annotations extends the generic @Component annotation by applying it as a meta-annotation. By applying the same technique, the @Component annotation provides an extension point for user-defined stereotypes. Spring can even auto-detect these annotated components as an alternative to XML configuration. For example, this excerpt is taken from the 2.5 version of the PetClinic sample application:

   <context:component-scan base-package="org.springframework.samples.petclinic.web" />

No additional XML is required for the web controllers since they use annotation-driven dependency injection and annotations for request mapping. I point this out, because the presentation specifically emphasized the verbosity of configuration for the web-tier:

public class ClinicController {

   private final Clinic clinic;

   public ClinicController(Clinic clinic) {
      this.clinic = clinic;

For up-to-date coverage of Spring's annotation support, see: Introduction to Spring 2.5 on The Server Side, or the latest version of Spring's reference manual - specifically the Annotation-based configuration section. Also, stay tuned to this blog and the Spring Framework home for some soon-to-be-released articles and blogs covering version 2.5.

2. Spring allows you to support multiple deployment environments but requires more configuration.

This one was actually presented as a Spring advantage but with an emphasis on the configuration overhead. The truth is any project where testing and agile development are taken seriously is going to require supporting "multiple deployment environments". In other words, this particular topic often gets distorted as if it applies only to multiple production environments. In reality, having to deploy to an Application Server during each development and testing cycle is a major obstacle to agility. Typically Spring users will modularize their configuration such that "infrastructure" configuration (e.g. DataSource, TransactionManager, JMS ConnectionFactory) is separate and dynamic properties are externalized. Since Spring provides support for replacing '${placeholders}' based on the externalized properties, the inclusion of different properties files typically becomes a transparent concern.

3. EJB with JPA, Spring with Hibernate

I must admit this one bothered me the most. In the comparison slides, the EJB 3 examples showed JPA with data-access via entityManager and the entityManager instance being provided with the @PersistenceContext annotation. On the other hand, the Spring examples used Hibernate and showed setter injection of the Hibernate SessionFactory. In my mind, this violates the first rule of a bona-fide "comparative analysis": use the most similar feature available on both sides of the comparison. In this particular case, Spring does provide support for using the JPA API directly (i.e. JpaTemplate is completely optional; direct usage of the 'entityManager' still participates in Spring transactions, etc), and Spring also recognizes the @PersistenceContext annotation. This support has been available since Spring 2.0 (final release was more than a year ago), so I don't understand why the comparison does not use JPA on the Spring side as well. Other parts of the comparison were clearly based on Spring 2.0, so this leaves the impression of being selectively out-of-date and revealing a bias. If this particular example were modified to be 'apples-to-apples', it would have undermined one of the main overall themes: that Spring requires more configuration whereas EJB 3 relies on standard annotations.

Now, even though I believe the usage of Hibernate rather than JPA on the Spring side distorted the comparison, it does simultaneously reveal a strength of Spring. If you do want to use the Hibernate API directly instead of relying on the JPA API, Spring enables that, and it does so in a consistent way with regard to Spring transaction management and Exception translation. This then opens up the opportunity to use Hibernate features that extend beyond the limitations of JPA, such as Hibernate's "criteria" query API. By the same token, if you would like to add some direct JDBC for data-access where ORM is overkill, that is also supported in Spring - even when invoked within the same transaction as Hibernate or JPA data-access.

4. Spring makes no assumptions, you have to provide configuration.

One specific example was the definition of a transaction manager. It was stated that you have to understand things at the container-vendor level to configure Spring integration. This is incorrect. For example, the following bean definition does not contain any container-specific information, yet Spring will auto-detect the transaction manager in all Java EE Application Servers:

   <bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager"/>

If you do want to leverage container-specific features such as per-transaction isolation levels, then Spring also provides a few specialized implementations: WebLogicJtaTransactionManager WebSphereUowTransactionManager, and OC4JJtaTransactionManager. Switching between these implementations is only a matter of changing this single definition.

In addition to this, the Spring configuration slides were unnecessarily verbose. I'm afraid this may also have been motivated by the goal of emphasizing that EJB unlike Spring relies on intelligent defaulting. For example, the slide showed:

   <tx:annotation-driven transaction-manager="transactionManager"/>

Actually, if there is a single 'transactionManager' defined within a Spring context, then that attribute does not need to be provided explicitly on the 'annotation-driven' element. That attribute is available solely for enabling the usage of multiple transaction managers within one application if necessary. These techniques of "auto-detection" and "intelligent defaulting" apply throughout Spring, such as the JMS 'connectionFactory' for a message-listener (which is implicit in the example of #6 below) and the automatic location of an existing MBean server or RMI registry.

On a positive note, it was actually mentioned as an advantage that Spring allows for "local" transaction management. While EJB requires JTA for transaction management, many applications do not need distributed transactions across two-phase commit capable resources. In such cases, Spring allows for simpler transaction managers with less-overhead: DataSourceTransactionManager (for JDBC), HibernateTransactionManager, or JpaTransactionManager. I would have expected to hear a bit more detail on that particular Spring strength if the goal was to accurately describe the pros and cons. For example, this is a huge benefit for testing outside of the container or developing within a lightweight IDE environment such as Eclipse or IDEA.

Furthermore, if you do require JTA for distributed transactions but want to run in a lightweight container like Tomcat or Jetty, Spring easily supports standalone JTA providers like Atomikos and JOTM. Sure Spring's transaction manager setup requires configuration of a single bean definition, but it really is a one-time cost - and well worth the benefit.

5. Spring does not have a stateful application paradigm.

The benefits of a stateless service layer are fairly well-established as a best practice, and Spring embraces that. Spring does provide scopes other than singleton however. Spring's "prototype" scope enables a distinct instance for each injection or lookup, and Spring 2.0 introduced web scopes: "request" and "session". The scoping mechanism itself is even extensible; it's possible to define and map a custom scope to the notion of a conversation. Spring also supports simple object pooling with the CommonsPoolTargetSource, but object pooling is rarely the best solution for state management.

More importantly, Spring does provide very robust, highly configurable state-management for web applications via Spring Web Flow. There the conversational state is managed transparently, contrary to the claim of this presentation that developers have to interact directly with the HTTP Session to manage state in Spring applications. Furthermore, the repository configuration is pluggable so that various strategies may be used for physical storage of the state (session, client, backend cache, etc.). Finally, the latest developments in Spring Web Flow include support for extended persistence context and fully integrated support for JSF.

6. Spring requires configuration of a container per MessageListener.

Spring 2.5 provides a new 'jms' namespace to greatly simplify the configuration of message-listeners. Notice that there is no separate configuration for a container per-listener. Multiple listeners share the configuration, and intelligent defaulting is used extensively:

	<jms:listener destination="queue.confirm" ref="logger" method="log"/>
	<jms:listener destination="queue.order…

Spring Java Configuration Moving Ahead

Engineering | Rod Johnson | November 05, 2007 | ...

Several users have asked whether we are committed to Spring Java Configuration, and how it sits with the annotation configuration option introduced in Spring 2.5. The answer is yes, we are committed to Java Config; and these two approaches are not mutually exclusive.

These two configuration approaches are quite different: the @Autowired annotation in the Spring Framework configures components using annotations in business objects, while Spring Java Config takes a unique approach of externalizing the annotations in dedicated configuration classes. Neither of these approaches is uniquely right…

Spring LDAP 1.2 Released

Releases | Mattias Arthursson | October 31, 2007 | ...

Dear Spring Community,

We are pleased to announce the release of Spring LDAP version 1.2. This is a major release that introduces a number of features and bugfixes.

            Download | ChangeLog | Documentation (HTML) | Documentation (PDF) | API

A summary of the more important changes:

  • Java 5 Generics support is now provided with the SimpleLdapTemplate and ParameterizedContextMapper classes.
  • Client-side LDAP transactions.
  • Several additional API methods, simplifying a number of common tasks.

About Spring LDAP
Spring LDAP is a Java library for simplifying LDAP operations, based on the pattern of Spring's JdbcTemplate. The framework relieves the user of the burden of looking up and closing contexts, looping through NamingEnumerations, encoding/decoding values and filters, and more.

The LdapTemplate class encapsulates all the plumbing work involved in traditional LDAP programming, such as creating, looping through NamingEnumerations, handling Exceptions and cleaning up resources. This leaves the programmer to handle the important stuff - where to find data (DNs and Filters) and what do do with it (map to and from domain objects, bind, modify, unbind, etc.), in the same way that JdbcTemplate relieves the programmer of all but the actual SQL and how the data maps to the domain model.

In addition to this, Spring LDAP provides Exception translation from NamingExceptions to a mirrored, unchecked Exception hirearchy, as well as several utilities for working with filters, LDAP paths and Attributes.

Spring-LDAP requires J2SE 1.4 for running. J2SE 1.4 and javacc is required for building the distribution binaries from sources. J2EE 1.4 (Servlet 2.3, JSP 1.2) is required for running the example.

Where to start
Download the distribution from the link above. The distribution contains extensive JavaDoc documentation as well as full reference documentation and a sample application illustrating different ways to use Spring LDAP.

The permanent home of Spring LDAP is at http://www.springframework.org/ldap.

Mattias Arthursson & Ulrik Sandberg, Spring LDAP Project Team

Spring 2.5 RC1 is here - introducing new configuration approaches

Engineering | Juergen Hoeller | October 24, 2007 | ...

As some of you will have noticed already, Spring 2.5 RC1 has finally been released on Monday and is waiting for you to give it a test drive! Spring 2.5 is in many ways the release that completes Spring 2.0's mission: providing the most flexible and most comprehensive configuration model for both Java 1.4 and Java 5. Spring 2.5 focuses on particularly comprehensive support for Java 5, introducing various further annotations options. I'd like to take the opportunity to point out the unifying themes behind this release:

Spring 2.5 allows for convenient externalized configuration while also keeping it as concise as possible. This is building on Spring 2.0's support for XML schema namespaces, with Spring 2.5 introducing new "context" and "jms" configuration namespaces. The latter is a particularly good example for the value-add that a Spring configuration namespace can provide - definitely worth adopting if you're using Spring 2.0 style message-driven objects! Additionally, Spring allows for programmatic bootstrap with no XML involved as well

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