A Java geek

Jul 31, 2011 JVM language

Do we need other languages on the JVM?

It seems a trend has caught on and accelerated recently: every organization worth his salt in the Java ecosystem feels the need to create its own language that runs on the Java Virtual Machine. Side by side with legacy languages like Jython and JRuby, and along more promoted ones like Scala, Red Hat announced Ceylon and now it’s JetBrain’s turn with Kotlin. However, the real question is not whether we need them (the answer is a simple 'no' since we created software without them), but

Jul 17, 2011 property spring

Property editors

In Java, property editors are seldom used. Originally, they were meant for Swing applications to transform between model objects and their string representations on the GUI. Spring found them another use: it’s typically what needs to be done when parsing a Spring beans definition file in order to create beans in the factory. Have you Spring users noticed you can set a number to a property and it is taken as such?

Jul 10, 2011 opensource

Give back to the community (please?)

Last week, I was ticked off by the behavior of a colleague: he complained the duplicated code panel in Sonar was not explicite enough. When I remarked he could give feedback to the Sonar team, he replied he had other things to do! As for me, I use OpenSource projects since a while back: Struts was my first, but now there are the whole Apache frameworks (Log4J, CXF and Commons just to name a few), Spring, Hibernate, Vaadin of course but also tools like Maven, Hudson/Jenkins, Sonar and the list g

Jul 3, 2011 security ssl tomcat

SSL your Tomcat 7

One thing I’m doing very often and always searching on the Internet is how to obtain a self-signed SSL certificate and install it in both my client browsers and my local Tomcat. Sure enough there are enough resources available online, but since it’s a bore to go looking for the right one (yes, some do not work), I figured let’s do it right once and document it so that it will always be there.

Jun 26, 2011 manifest webapp

Get the handle on the MANIFEST.MF in a webapp

Code review is part of my job, and you cannot know the crap I’ve seen. Like someone pointed out, it’s also sometimes the crap I’ve written 🙂 In all cases, however, it’s because some developers do not have deep knowledge of how things work: most learnt something (in university or from a senior developer) years ago and don’t challenge this information regularly though technology evolve. Others just google the problem at hand and copy-paste the first snippet in their

Jun 19, 2011 jboss maven repo1

Maven repositories in anger!

Every build systems worth his salt acknowledges Maven dependencies repository. Even those vehemently opposed to the way Maven does things, like Gradle, still uses repo1. Wait, repo1? If there was only repo1. But nowadays, every project publishes its artifacts in its own repository. For some providers, like SpringSource and JBoss, I think it may be for marketing reasons. But whatever the reasons are, it only makes the job of the enterprise repository manager harder, since he has to reference all

Jun 5, 2011 hibernate

Hibernate hard facts – Part 7

This is the 7th post in the Hibernate hard facts focus series. In this post, we’ll have a look at the difference between saveOrUpdate() and merge(). Hibernate’s way for updating entities is through the update() method. We can get an object, detach it from the session and then update it later with no problem.

May 22, 2011 security servlet

New declarative security features in Servlet 3.0

Servlet 3.0 is not only about the replacement of the web.xml deployment descriptor by annotations. In this article, we’ll see what improvement it makes in the realm of security. In Servlet 2.5 (and before that), declarative security was about the following features: authentication method (BASIC, FORM, etc)authorization to differents parts of the application (web application resources)data confidentiality and integritysession time-out Servlet 3.0 adds standardized ways regarding two conf

May 16, 2011 blackbelt vaadin

Vaadin courses on JavaBlackBelt

For those of you who haven’t heard of JavaBlackBelt, it’s an e-learning community site. Once registered, users can use the site in a variety of ways: First, one can take courses on a variety of programming-related subjects.Then, one can pass exams on these subjects. Each exam is made of questions one has to anwser in a limited time frame. Passing an exam gives you knowledge points; with enough knowledge points, you get the next belt, until the fabled black belt!One can also contribut

May 2, 2011 vaadin

New Filter API in Vaadin 6.6

Vaadin is available in version 6.6 preview since this week. Among other interesting enhancements, one surely caught my attention, the new Filter API. To understand why it’s so interesting, one must know how it’s handled in version 6.5 and before. But first, a word about filters in Vaadin: they are used in containers, which handle collections of items, in order to sort out eligible items.