Category Archives: Free Software

Free Software (FLOSS)

QT Application with Java. Possible? Yes QT Jambi does it.

If you’ve never heard about it, you can build rich cross-platform GUIs with Qt Jambi., while coding in Java. What?
Yes, QT Jambi is a QT Binding to Java, allowing you to develop QT GUI using Java instead of C++.
It practically is the same thing as Java-Gnome library which is a GTK+ binding.

QT Jambi is still maintained as opposite to rumors. And the last snapshot was build on 11 November 2012.
If you want to give it a shot, the following is a ‘get started’ tuto:


  • OS: Ubuntu 12.10 AMD64
  • Desktop: Unity
  • IDE 1: Netbeans 7.3
  • JDK: Oracle JDK 1.7.u10
  • IDE 2: Eclipse Juno

First, install Qt Jambi from its PPA:

sudo add-apt-repository ppa:qtjambi-community/libqtjambi-snapshots && sudo apt-get update && sudo apt-get install --install-suggests libqtjambi-snapshot qtjambi-examples-snapshot qtjambi-designer-snapshot ant-qtjambi-snapshot libqtjambi-redist-snapshot

Then, use this script, to tell your JDK where to find corresponding QT libraries used by QT Jambi:


#| Title: CopyJambi
#| Author: Hanine HAMZIOUI
#| Contact: <>
#| Date:  Sat 15 Dec 2012 03:57:00 AM WET
#| License: GNU GPL v3+
#| Description: Create symlinks to QT libs in default JDK for Jambi.
#| Version: 1.0
#| Environment: Netbeans 7.3 on Ubuntu 12.10 AMD64
#| Compliance: bash, zsh, ksh, dash, sh

# sudo add-apt-repository ppa:qtjambi-community/libqtjambi-snapshots
# sudo apt-get update
#sudo apt-get install --install-suggests libqtjambi-snapshot qtjambi-examples-snapshot qtjambi-designer-snapshot ant-qtjambi-snapshot libqtjambi-redist-snapshot

# Pick the JDK path
if [ -n "${JAVA_HOME}" ]; then jdk=${JAVA_HOME}
    if [ -d "/usr/lib/jvm/default-java" ]; then jdk=/usr/lib/jvm/default-java
    else whiptail --msgbox "No JAVA_HOME was found. Script will abort." "$LINES" "$COLUMNS"; exit 0

# Two Temporary files that receive names of libraries to be copied

# Get the names of libraries to be copied
ls /usr/lib/x86_64-linux-gnu/ | grep libQt | sed -e '/.prl$/g' -e '/.a$/g' -e '/[0-9].[0-9]$/g' | perl -ne 's/^$//g || print' > ${tmp1}
ls /usr/lib/x86_64-linux-gnu/ | tr '[:upper:]' '[:lower:]' | grep libqt | sed -e '/.prl$/g' -e '/.a$/g' -e '/[0-9].[0-9]$/g' | perl -ne 's/^$//g || print' >> ${tmp1}
ls /usr/lib/jni |  tr '[:upper:]' '[:lower:]' | grep trolltech > ${tmp2}
ls /usr/lib/jni |  tr '[:upper:]' '[:lower:]' | grep jambi >> ${tmp2}

# Create symbolic links to QT libraries
while read line; do
sudo ln -v -s /usr/lib/x86_64-linux-gnu/${line} /usr/lib/${line}
sudo ln -v -s /usr/lib/x86_64-linux-gnu/${line} ${jdk}/jre/lib/amd64/${line}
done < ${tmp1}
echo "Copied ${count} QT libraries Symbolic links"

# Create symbolic links to Jambi Libraries
while read inline; do
sudo ln -v -s /usr/lib/jni/${inline} ${jdk}/jre/lib/amd64/${inline}
sudo ln -s -v /usr/lib/jni/${inline} /usr/lib/${inline}
done < ${tmp2}
echo "Copied ${i} Jambi QT libraries Symbolic links"

# Remove temporary files
if [ -f ${tmp1} ] || [ -f ${tmp2} ]
    then rm -v ${tmp1}; rm -v ${tmp2}

# Make sure the user system is amd64
arch=$(uname -i)
if [ "${arch}" = "x86_64" ]; then eval OPERATION
else whiptail --msgbox "Your system architecture is not AMD64. Script will not continue. Abort." "$LINES" "$COLUMNS"
exit 0

The above script will create symbolic links in your JDK path. If you want you can copy the libraries instead of just symlinking them.

Next step is to create a Java Project in Netbeans and import Qt Jambi library in classpath as well as QT Jambi Demos library. (You’ll find them in /usr/share/java/)


Here is a screenshot of a demo example :


You can test with a simpler example (Hello World):

package jambi;

import com.trolltech.qt.gui.*;

public class HellowWorld {

public static void main(String args[]) {
QPushButton hello = new QPushButton("Hello World!");
hello.resize(120, 40);
hello.setWindowTitle("Hello World");;


When running a QT Jambi java file, you might encounter this error :
# A fatal error has been detected by the Java Runtime Environment:
# SIGSEGV (0xb) at pc=0x00007f6b95e362ba, pid=10602, tid=140100171314944
# JRE version: 7.0_10-b18
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.6-b04 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C [] QWidgetPrivate::deleteTLSysExtra()+0x3a
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
# An error report file with more information is saved as:
# /home/hanine/Workspace/test/jambi/hs_err_pid10602.log
# If you would like to submit a bug report, please visit:

Yet, entering : ulimit -c unlimited does not help at all. It sounds like an old bug related to Java HotSpot, where a zip file is read and modified in the same time. In other situations this bug is overriden using -Xmx option (e.g. -Xmx2900m : Maximum Memory : 2.9 GB )
E.G: java -Xmx:1864m -Xms:1864m myapp.jar sets minimum & maximum java memory heaps to 1864 MB for myapp.jar.
So, it appears that in almost all cases, a java file with the following statements will produce this error:

 public static void main(String args[]) {

        Wiggly d = new Wiggly(null);;


So to get rid of this error, change the code to look like this instead (Still investigating on the root problem though):

 public static void main(String args[]) {
        new Wiggly(null).show();


Running your Qt Application from terminal

When you clean and build with Netbeans, you’d get a Jar File in your project workspace, in a folder named dist.
Make this jar file executable : chmod +x /path/to/this/jar/file.jar
and run it from terminal: java -jar /path/to/this/jar/file.jar

Qt Application executed as a JAR file.

Qt Application executed as a JAR file.

Eclipse Juno IDE

You can achieve the same thing using Eclipse if it’s your preferred IDE. Just make sure you install qt-jambi from Launchpad PPA and run the above script:

  • – Use the script from above or just download it from here : QtJambiCopierSCript
  • – Save it in your Desktop and run : bash ~/Desktop/
  • – Follow instructions if any.
  • – Open Eclipse Juno, Create a Java Project and add external libraries from /usr/share/java/
  • – Adding the qtjambi.jar and qtjambi-examples.jar does the job.


GUI Designer

Unlike Java-Gnome binding library which does not yet integrate with GUI designer GLADE, Qt Jambi integrates with QT Designer.
If you followed instructions above, go to your Terminal and type:


bash /usr/bin/

This will launch QT Jambi Designer. Henceforth, you can start designing visually your GUI. Once finished, save the work as a "*.jui" file, which you would reuse as your Application UI.
Normally, Qt Designer produces a file with "*.ui" extension; but QT Jambi team has modified the thing with custom modifications that allow better integration and generation of UI java files.
We will cover this later in this same post.
Thanks for reading.
N.B: Qt Jambi Community website is down since yesterday (14th December).
You can browse other useful resources that will get you accustomed to QT Jambi quickly: QT JAMBI RESOURCES

Calculate your Body Mass Index

Bomico is a tiny java application that computes an individual’s body mass index based on some measurements.

The application is free software released under GPL 3.

You can contribute to it if you want to. Checkout the code at . You must register to GitHub in order to become a contributor (it’s free for open source projects).

If you want just to install it: you can download it here :

Note that if you’re running Ubuntu 12.04, Bomico supports Ubuntu Global menu and thus HUD. Be sure before installation, you have a Java JRE installed (Oracle JRE or OpenJDK 6 or 7).

After installation you can check that installation was completed by typing the following command in your Terminal:

bomico --version

If you download and want to run the jar file, (supposing you have set your java home classpath already), copy the jar file (bomico_1.0.2.jar) to your desktop and do as follows, in a terminal:

java -jar ~/Desktop/bomico_1.0.2.jar

bomico-screenshot (Ubuntu 12.04)