Xebia Blog

When using Oracle, or other MVCC (Multi Version Concurrency Control) databases like Postgresql or MySql in combination with InnoDb, a transaction with the SERIALIZABLE isolation level doesn't always block (a pessimistic approach) when it conflicts with another transaction. Instead a more optimistic approach is used. This approach however can lead to an abort of the transaction with the feared: "ORA-08177: can't serialize access for this transaction", which in essence is just an optimistic locking failure. (more...)

Filed under: Concurrency Control, Oracle
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While developing and testing the Java EE web applications, people often needs a way to immediately web-view the changes that they have made in their JSP or HTML or Javascript.

For people who are using Eclipse or intelliJ as their IDE might also like to see their changes in serverside Java files applied over the deployed webapp's immediately.

Lets see how this can be done using Maven (more...)

Filed under: Java
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Concept to auto-wire relationships among spring enabled beans has always been there. The idea with auto-wiring is to get away from the tedious task of specifying and more importantly maintaining explicit wiring. Originally it was supported to be done by name, by type, by constructors or auto-detect and then you had the option to auto-wire all or specific beans within a context. But now with Spring 2.5 the auto wiring concept has taken a whole new meaning and so is the debate if we really want to do auto-wiring.

Spring 2.5 has a new @Autowire annotation. @Autowire annotation let us do much fine grained auto-wiring then was possible before and also it make us much more explicit then was possible in pre Spring 2.5 times
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Filed under: Java, Spring
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Last week, the first QCon conference in the US was held. The conference is targeted at team leads, architects and project managers and aims to be the best environment for learning and networking. It is a relatively small-scale conference (about 400 attendees) that provided an intimate atmosphere and allowed for plenty of discussion and networking with other attendees and speakers. These are my impressions and topics I found most interesting.
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Filed under: Java
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Last week I visited the TelemanagementWorld conference and with Andreas and John we did a session to explain why the Order Management API is perfect for converging environments like Telco, Cable, ISP, Mobile. The presentation can be downloaded from the TMForum web-site (session SYS33). But, because it is only accessible to TMForum members or a visitors of the conference, I'll provide a summary below.

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Filed under: Java, Telecommunications
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Since a couple of weeks me and some colleagues are working on a project in which need to produce a fancy and flashy website. To achieve this we are teamed up with some html/css experts from lostboys. As we did not want to temper with the html code the lost boys (and girls) produce, our colleague Okke Harsta proposed wicket as web framework. This is the first time I ever used wicket and I must say I am amazed by how easy and natural it is to work with. We can leave all the html code to the specialists and only need to produce the Java code, which basically feels like programming Swing. I could give all kinds of examples in this blog on how easy wicket is in for instance adding Ajax behavior, but I think it better that you check it out yourself. I highly recommend you put it on top of your which-web-framework-do-I-need-to-choose-for-my-new-project list.

Filed under: Java
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The following post talks about my first brush with Guice based on a couple of hours that I spent on it for the past few days. I would not get into burning fire of comparing Guice with Spring as there has already been a lot of debate on that. Personally in my view it is comparing apple with oranges. We can probably just make comparison between how DI works on Spring and how it works on Guice but then we know that Spring is much more than DI, it is a feature full comprehensive stack.

So not getting into that path any further back to DI with Guice.

Guice wholly embraces annotations and generics. The idea is that annotations finally free you from error-prone, refactoring-adverse string identifiers and frees you up from the XML configuration hell. Guice injects constructors, fields and methods (any methods with any number of arguments, not just setters)

The injection process for Guice is a two step injection process.
1.Define the Bindings.
2.Inject the concrete implementations at the right places.

Let us look at how it is done...
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Filed under: Java
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For testing my applications I like to use FitNesse and for writing my applications I tend to use Spring a lot. Since there is no way in FitNesse to override the mechanism how the Fixtures are instantiated you need to somehow load the Spring context and get the beans you want to test from the Spring context. You can of course do this by hand and retrieve the beans from the application context, but this kind of clutters your fixture code. Better is to let Spring take care of the wiring.
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Filed under: Java
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