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Request-Reply JMS with Spring 2.0

Several months ago, I posted a blog entry introducing Spring 2.0’s support for Message Driven POJOs. While many people are now familiar with that feature, Spring 2.0’s JMS remoting features have received less attention. Essentially, this remoting functionality provides a JMS-based version of Spring’s general approach to remoting as exhibited in its support for RMI, Hessian/Burlap, and its own HttpInvoker.

For those unfamiliar with Spring remoting, the general idea is to configure a non-invasive exporter on the server-side and a proxy generator (a Spring FactoryBean) on the client-side.

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BeanInitializer: wiring dependencies in unit tests

One of the things that irritates me the most about unit testing some classes in a Spring context, is initialising them with all their dependencies. This is especially true of Spring framework extensions, like FactoryBean implementations or *Aware implementations. It is cumbersome to add all the dependencies, and easy to forget to call the bean lifecycle methods, like the afterPropertiesSet method from InitializingBean.

The Spring base classes for unit testing help quite a lot, but there are still some things that are fiddly. E.g. in many cases it is necessary to disambiguate autowiring, so that collaborators are given the correct implementation. Also, to benefit from the lifecycle execution you have to be testing a bean instance from the current configuration, which isn’t always convenient.

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Amsterdam Java Meetup scheduled for April 13th

Mark you calendars! In about two weeks, I’m hosting another Amsterdam Java Meetup; the quarterly event in the Netherlands where all people that have something to do with Java (but hey, we’re friendly; .NET guys are welcome too!) can have a chat and a drink. No technical sessions, no presentations, no keynotes, just drinks and chatting.

We have been organizing the Java Meetups for a while now and the attendance has grown from about 20 in December 2005 to about 60 or 70 last January.

So, spread the word and come join us (ah, and don’t forget, the first couple of rounds are paid for).

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AOP Context Binding With Named Pointcuts

There a a ton of new features in Spring AOP including the AspectJ pointcut language, the <aop:*/> namespace, and the @AspectJ syntax support. But by far one of the most powerful aspects (forgive the pun) is the AOP context binding.

For example, let’s say you want to advise a method that takes a String as an argument.


public interface HelloService { String getHelloMessage(String toAddHello); }

To advise this method, you’d write a pointcut that looked for a String return type, all implementations of the HelloService interface and the getHelloMessage(String) method.

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NY Java SIG Overflows

Every so often I get to experience something pretty amazing about the popularity of Spring, Interface21, and our people.

Last night was one of those such moments. Rod spoke at the NY Java SIG in Manhattan. Long time NY Java SIG coordinator Frank Greco sent out an email announcing the Java SIG late on a Sunday night about two weeks ago. By Monday morning at around 9am the event had hit a maximum number of registrations of 300 (the conference room at Google gets trouble from the fire codes when they exceed 260). Effectively the Java SIG had sold out in about a business hour. I think with friends and guests the total registered list was 340. Amazingly, people were turned away at the door once the room filled to 260. For them, I am sorry they didn’t get to see Rod speak but maybe they can come down to Philadelphia for the Emerging Technologies in the Enterprise show.

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Why Open Source Businesses are not like Wal-Mart

Hopefully one or more open source businesses will be among the standout successes of early 21st century capitalism. However, it’s interesting to look back at one of the standout successes of late 20th century capitalism for an instructive example of one of the unusual challenges facing open source businesses.

Wal-Mart’s history is well known. The first Wal-Mart opened in Rogers, Arkansas in 1962. Five years later there were 24 stores across Arkansas. In 1968, Wal-Mart opened its first stores outside Arkansas, in Missouri and Oklahoma. Both those states, of course, neighbour Arkansas. Wal-Mart’s expansion thereafter continued to be in concentric circles around its home base, enabling logistical and cultural challenges to be overcome gradually and execution to continue to be highly efficient. Despite enormous success in Wal-Mart’s home market, wider geographical expansion has not always proven successful–as in Germany.

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CarPlant not accepting null CarModels

Last Friday I finished a training session at a client of ours. Because I had some time to kill in the hotel I was staying in, I polished the sample application I coded up during the training to post it online for the guys of the training. Usually I try to find a little sample application specific to the client’s domain to use during the training. This makes it a bit more lively instead of some of the HelloWorld examples.

This client is a big car brand, that have adopted Spring widely throughout their organization. That’s why I created a CarPlant system capable of producing cars. Below you can find a little UML diagram displaying the (rather tiny) domain model and services in the system.

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New on the Spring forum: regular polls

A while ago, we were thinking about doing a big survey among Spring users to render feedback about parts of the framework. We’d include questions like ‘which Java version are you using’, but also ask you which Spring feature you like, dislike, et cetera.

Partially because of lack fo this, but also because for now, we don’t want to force Spring users to fill out huge surveys, we never got to actually doing this.

In the past half hour, I’ve set up a nice alternative on the Spring Framework forum. From now on, we’ll be hosting a series of polls on the forum. The polls are basically very simple multiple choice questions and the results will be available to everybody. In addition to the poll, we’ll also give some background information on each of the options.

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Maven Artifacts

At long last I can finally say that SPR-1484 is resolved. Opened on 20 November 2005 with 121 votes, 63 watchers, and even its own anti-ticket this issue rates as one of the all time biggies. In the last 10 minutes I’ve uploaded the maven artifacts for Spring 1.2.9 to our local repo and you should be seeing them replicated onto the central maven repo in the next 6 hours or so.

You will notice on the Spring JIRA issues such as SPR-2704, SPR-1383, and SPR-3198. What this means is that we’re not done improving our builds and and we will continue to respond to the community. In fact, we’ve got some really cool new tools that I can’t wait to show off in upcoming posts.

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Oracle Contributing Oracle Application Server Integration Code to Spring Framework

On the theme of application servers embracing Spring, another update. Oracle have been working on value added integration with their application server.

This is similar to what we have with WebLogic 8.1 and above in WebLogicJtaTransactionManager. The OC4JJtaTransactionManager should be used in place of the generic JtaTransactionManager in an OC4J environment, and provides the following benefits:


  • Direct access to the transaction manager and helper classes without having to use
    JNDI lookups

  • Auto-detection of server version to get the most out of the different transaction manager implementations in different versions

  • Control over transaction isolation level: a very useful feature not available in JTA

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