LookAndFeel chooser

You will not dispute that modern desktop application needs some theming, right? And, being Swing developer, few times you tried to solve this problem, didn't you?..

I have solution now: JLAFChooser.
Now, you can just put JLAFChooser component into your setting dialog, and it will make LookAndFeel chosing possible in runtime. Now you have no need to hardcode all the LookAndFeels you know into your classes or XML files, and user can just download few LookAndFeels and put it somewhere in classpath to make it available to JVM.

It has two main variants: when Apply is allowed and when not.

When Apply is allowed your user can choose something from list and check it at once, and may be choose something else.

When Apply IS NOT allowed you can just show list of possible LookAndFeels, and save somewhere to preferences user selection, to apply it next startup.

Usage is similar to JColorChooser, with few extensions - you can get LookAndFeel instance, it's name or it's class name. Methods to apply and restore LookAndFeel are public, you may use them for your controls.

PS: feel free to mail me for suggestions, bugs, or just to talk about Java, Swing, religion, fantasy or anything...


current KDE version determination

I have a problem. KDE4 is comming, and I need to determine current running version from Java application. Do you know how?

After some investigations I found few ways. KDE is setting it's own env variables. For KDE3:


For KDE4:


But it works only for SUSE, Kubuntu have only KDE_SESSION_VERSION=4 and KDE_FULL_SESSION=true. And this is only for 8.04 KDE4 release of Kubuntu, there was no such flags in 8.04beta. So, determination is simple:

public static boolean isKDERunning() {
  return "true".equals(System.getenv("KDE_FULL_SESSION"));

public static boolean isKDE4Running() {
  if (!isKDERunning()) {
    throw new IllegalStateException("KDE is not running");
  return "4".equals(System.getenv("KDE_SESSION_VERSION")) ||

If you feel paranoid and want to get 100% result it will be better to run Konsole (konsole --version) and parse output. Output for different versions looks like this:

konsole --version
Qt: 3.3.8
KDE: 3.5.7 "release 72"
Konsole: 1.6.6

/usr/bin/konsole --version
Qt: 4.3.4
KDE: 4.0.3 (KDE 4.0.3) "release 9.1"
Konsole: 2.0

So, parsing code:

public static boolean isKDE4Version() throws Exception {
  Process process = Runtime.getRuntime().exec("konsole --version");
  InputStream in = process.getInputStream();
  byte[] buffer = new byte[32];
  ByteArrayOutputStream out = new ByteArrayOutputStream();
  int read = 0;
  while ((read = in.read(buffer)) >= 0) {
    out.write(buffer, 0, read);
  String output = out.toString();
  int indexOfKde = output.indexOf("KDE:");
  if (indexOfKde >= 0) {
    char v = output.charAt(indexOfKde + 5);
    return '4' == v;
  throw new IllegalStateException("KDE version information not found");

And don't fear performance issues - on my Athlon X2 6000+ this operation takes only 26 millis!