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!

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