View Full Version : Java/Kubuntu: Find program associated with a file

July 24th, 2009, 01:54 PM

Does anybody know how to find the program associated with a certain file on Kubuntu? For example, I've got a PDF file and I'd like open it with the system's default PDF viewer (but from another program rather than by just double-clicking on it).

Thanks in advance!

July 24th, 2009, 02:57 PM
-- bad post --

July 24th, 2009, 03:51 PM
It's not trivial, unless you find a Java library you can use right away.
The associations can be found by reading and parsing the data from the corresponding .desktop files which are scattered across the system in given directories.
About the location of these directories and the format of the .desktop files you can learn from freedesktop.org, for example the .desktop specs are here:

A sample implementation (in C++ though) of how to search for all the folders that contain .desktop files:

vector<Glib::ustring>* Settings::listDesktopEntryDirs() {

vector<Glib::ustring> *pv = new vector<Glib::ustring > ();
const Glib::ustring apps = "applications/";

//highest priority to settings from home dir
Glib::ustring sLocalDataDir = Glib::get_user_data_dir();
if (sLocalDataDir.size() > 1) {
pv->push_back(Glib::build_filename(sLocalDataDir, apps));

Glib::ustring sPaths = getenv("XDG_DATA_DIRS");

//if not set use defaults
if (sPaths.size() < 2) {
sPaths = "/usr/local/share/:/usr/share/";

const Glib::ustring sep = ":";
size_t iStart = 0;
size_t iEnd = 0;

while (true) {
iEnd = sPaths.find(sep, iStart);
if (iEnd == Glib::ustring::npos) {

Glib::ustring sToken = sPaths.substr(iStart, iEnd - iStart);
iStart = iEnd + 1;

pv->push_back(sToken + apps);

if (iStart < sPaths.size()) {
pv->push_back(sPaths.substr(iStart, sPaths.size() - iStart) + apps);

return pv;


July 25th, 2009, 11:58 AM
@ froggyswamp

Thanks for your answer. Is there really no easier way to do this? I was hoping for a command line tool or something... :(
Besides, I couldn't find a library for this either.

July 25th, 2009, 12:36 PM
You can use xdg-open for that.

July 25th, 2009, 01:17 PM
OMG sorry, I thought for some reason you want a list of "Open with" apps.

Since Java 6 you can do this, example:

import java.awt.*;

public class Main {

public static void main(String[] args) {
Desktop d = Desktop.getDesktop();
try {
d.open(new java.io.File("/home/fox/Desktop/books/GTK Development 2007.pdf"));
} catch( Exception exc) {


but from another program
Oops, I'm confused.

July 25th, 2009, 01:32 PM
@ moonraf
xdg-open is just what I was looking for, thanks!

@ froggyswamp
Last time I checked the Java Desktop API only worked on Gnome, but not on KDE... :(