Findbugs, PMD, Checkstyle & Dependency Finder in Netbeans

The Software Quality Environment project provides Netbeans plugins related to code quality.

Unfortunately they are not in the default Update Centers so you have to add the SQE Update Center Manually.

Unfortunately again, at the time of writing, the SQE web site provide a wrong Update Center URL that leads to a 404. Who mentionned ? :)

So, without further ado, here is the SQE Update Center URL:

Once the Update Center is added, the Available Plugin catalog contains a Quality category that contains cited plugins.

All the plugins are working fine on Netbeans 7.0.


Getting used to gradle, a case study : developing Qi4j

Lately Qi4j moved from maven to gradle:

Qi4j community migrated away from Maven after several years of frustration, especially around release management, versioning and cross-module dependency resolution issues, in Feb 2011. The tool of choice is now Gradle.

What ?

The case study I want to describe today is quite simple. I’m writing an application using Qi4j, it’s build is maven based. As I am contributing to Qi4j alongside the development of my own application I’m using the development branch of Qi4j most of the time. In maven terms it means my application depends on the last version SNAPSHOT. I want to continue working this way so I’ll describe here how to use the Qi4j build system for this use case.

In other words, you’ll learn how to manage the Qi4j build system for developing Qi4j and use it in maven projects.

What not ?

I will not talk about IDE support here, only build systems, namely maven and gradle.

Making it work

The main goal is to find gradle commands for different aims and make their run as short as possible.

I used the same computer for all time mesures present in this post, a Samsung netbook N150 with 2GB RAM and a Vetrex II solid state drive from OCZ.

Commands described here last from 45 minutes to 5 minutes for building and installing the whole Qi4j ecosystem in the local maven repository. When dealing with single modules all this gets very quick. For example org.qi4j.core.api can run in 20 seconds when skipping tests and javadoc.

Here are some example gradle commands. I use the gradle daemon to get rid of the startup time.

$ gradle install -Dversion=1.3.0-SNAPSHOT

This one takes forever, it will buid and install locally all artifacts (main, -sources, -javadoc),run tests and then generate the qi4j-sdk distribution archives. Took my netbook ~40 minutes.

$ gradle -x test -x javadoc -x javadocJar -x sourceJar -x :javadocs -x :distLayout -x :tarBinaries -x :tarSources -x :zipBinaries -x :zipSources install -Dversion=1.3.0-SNAPSHOT

This one build and locally install all main artifacts skipping tests, javadocs, sources and distribution archives. Took ~5 minutes on my netbook.

$ gradle -a -x test -x javadoc -x javadocJar -x sourceJar -x :javadocs -x :distLayout -x :tarBinaries -x :tarSources -x :zipBinaries -x :zipSources :org.qi4j.libraries:org.qi4j.library.servlet install -Dversion=1.3.0-SNAPSHOT

This one build and install only the org.qi4j.library.servlet artifact, skipping tests, javadocs and sources archives and ignoring changes in other modules. Took ~15 seconds, now that gets usable !

Theses are quite hairy, aren’t they?

Getting easy

To ease my work I wrote some shell scripts around gradle. They are available on github here:

Here is the help of the qi4j-build command:

paul@petit:~/src/github/qi4j-sdk$ qi4j-build 
qi4j-build [-p group:project] command [flags]

  -p Select the target project
    group can be core, library, extension, tool, sample or tutorial
    project is the base name of the targeted submodule

  Available commands
    clean            Clean output
    test             Run tests
    install          Install only main artifacts
    devinstall       Install javadoc and sources artifacts
    distinstall      Install distributions archives

  Available flags
    skipTests        Skip tests

    qi4j-build clean
    qi4j-build devinstall
    qi4j-build library:servlet test
    qi4j-build libraries install
    qi4j-build distinstall

Feel free to report issues, fork and request pull.

Maven, help-plugin and continuous integration

MavenWhen a maven build fails in continuous integration you often end up reading the console output, sometimes browsing kilobytes of text (yes, maven outputs a lot and can seem chaotic). To ease build debugging you can tell maven to output some introspectional data.

The idea is to use the maven-help-plugin a lot but you can add others and home made ones to the mix. To quickly see what can easily get outputed my maven you can play with the following commands :

mvn help:system
mvn help:active-profiles
mvn help:effective-settings
mvn help:effective-pom

Here is a sample output of the active-profiles goal :

[INFO] ------------------------------------------------------------------------
[INFO] Building my-project
[INFO] task-segment: [help:active-profiles] (aggregator-style)
[INFO] ------------------------------------------------------------------------
[INFO] [help:active-profiles]
Active Profiles for Project 'myGroupId:myArtifactId:jar:0.1.0-SNAPSHOT':

The following profiles are active:

- continuous-integration (source: settings.xml)
- libs-daily (source: pom)

[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------

Adding such output at the very start of builds is really handy when setting up a CI service or during build refactorings.

Note that if a profile is defined in a parent pom it won’t be shown as activated in submodules by help:active-profiles but if you read the help:effective-pom output on one of the modules you’ll see it’s effectively activated, see this comment in MNG-3228.

Hope this helps.

If you read this, you certainly want to read Maven Continuous Integration Best Practices.

Unit test JPA Entities with in-memory Derby/JavaDB

HibernateAbout two years ago I blogged about using HSQLDB to unit test JPA entities. This year, Apache released a Derby version allowing you to use an in memory backend. As I use Derby in software I write, being able to run unit tests on the very same SGBD but in memory is a real gift.

For reference, here is a link to my previous post titled Unit test JPA Entities with in-memory database. What follows is just the very same method applied to Derby.

Continue reading “Unit test JPA Entities with in-memory Derby/JavaDB”

Isolated VirtualBoxes network on a Linux laptop

I like emulation/virtualization a lot. I used to use Win4Lin and VMWare for testing new systems/applications I now have switched to VirtualBox mainly because of the automation scripting tools (VBoxManage and friends).


I work/play on a linux laptop and need to run several virtual machines interconnected in an isolated network and the VirtualBox network configuration can give headaches, it gave me some : ) During the setup I had to write things down on paper, walk around chewing my pencil, scratch my head .. so I will share theses notes here hoping it will be usefull to someone.


For a 10000 feet view of the setup explained here, a simple picture is better than many words :

Virtual Network Overview
Virtual Network Overview

Host->VBoxes: permanent
Host->External: independant the virtual network
VBoxes->VBoxes: permanent
opt switchable per vbox
VBoxes-->External: virtualbox nat

Continue reading “Isolated VirtualBoxes network on a Linux laptop”

Customer i18n overlays with GWT

GWTI’m building a web backoffice for an IT product with GWT for several month now. I had to internationalize all the UI. GWT provides several mechanisms for i18n. I use Constants and Messages because I love the compile time check and the fact that deferred binding permutations provide a download as small as possible to the users.

All this worked well until we wanted to provide customers the ability to change how things are named in our product. In the UI layer of course !

Like said above, GWT is using deferred binding to provide a Constant/Message implementation per locale. I extended this mechanism to provide a Constant/message implementation per locale and a given GWT property.

Enough talk, lets see how this is done.
Continue reading “Customer i18n overlays with GWT”

A simple^W dumb Map wrapper to use with JAXB

Java XML

I sometimes need to use java.util.Map objects in WebServices. As I’m building all my WebServices with the JAX-WS RI (using the Metro bundle). The block responsible for XML (un)marshalling of POJO, named JAXB, does not allows to directly use Maps as a soap operation parameter. For this purpose I’ve written the following simple class that allows me to wrap Maps in a POJO that JAXB is able to (un)marshall :

public class JAXBMapWrapper<KT, VT> {

    private Map<KT, VT> wrappedMap;

    public JAXBMapWrapper() {
        wrappedMap = new HashMap<KT, VT>();

    public Map<KT, VT> getWrappedMap() {
        return wrappedMap;

    public void setWrappedMap(final Map<KT, VT> givenMap) {
        wrappedMap = givenMap;


ATTENTION: I posted this some days ago and removed the post after understanding that this is simpler on the service side but that the client side gets cumbersome generated classes.. but google cache indexed the post in less than half a day.

Just don’t use this ! :) If you need to transmit Maps over JAX-WS webservices, do it the XmlAdapter way as advertised in the official Unofficial JAXB Guide instead.