OPERATING SYSTEM(S):
Linux (Ubuntu)

FULL JDK VERSION(S):
1.6.0_13

STEPS TO REPRODUCE:

1. Create file called "abc.xyz" & opens it with "gedit".

2. Change the associated registered application: Right click on the file
   and select properties. Go to "opens with" tab and select "firefox".

3. Compile and run Hello.java, compile it and run as follows.
     javac Hello.java
     java Hello abc.xyz


TESTCASE
--------
import java.awt.Desktop;
import java.net.URI;
import java.io.*;

class Hello {
    public static void main(String args[]) {
        Desktop desktop = null;
        if (Desktop.isDesktopSupported()) {
            try {
                desktop = Desktop.getDesktop();
            } catch (Exception he) {
                System.out.println("GraphicsEnvironment is headless, got a Headless Exception");
            }
        } else {
            System.out.println("Desktop class is not supported on this platform");
        }

        try {
            File file = new File(args[0]);
            URI uri = file.toURI();

            if (uri != null) {
                //System.out.println(uri.toURL());
                desktop.browse(uri);
            } else {
                System.out.println("URI is null");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}


Observed Result:
It is still uses "gedit" to open abc.xyz.

Expected Result:
It should use firefox to open the file.

ANALYSIS
--------
The behaviour can be replicated with a standalone C testcase:

#include <stdio.h>
#include <dlfcn.h>

typedef int gboolean;
gboolean (*gnome_url_show) (const char *url, void **error);

int main() {
    void *gnome_handle;
    void *vfs_handle;
    gboolean (*gnome_vfs_init) (void);
    vfs_handle = dlopen("libgnomevfs-2.so.0", RTLD_LAZY);

    if (vfs_handle == NULL) {
        printf("\n cannot load libgnomevfs");
        return 0;
    }

    gnome_vfs_init = dlsym(vfs_handle, "gnome_vfs_init");

    if (gnome_vfs_init == NULL) {
        printf("\n gnome_vfs_init is NULL ");
        return 0;
    }

    (*gnome_vfs_init)();
    gnome_handle = dlopen("libgnome-2.so.0", RTLD_LAZY);

    if (gnome_handle == NULL) {
        printf("\n cannot load libgnome-2.so.0 ");
        return 0;
    }

    gnome_url_show = dlsym(gnome_handle, "gnome_url_show");

    if (gnome_url_show == NULL) {
        printf("\n gnome_url_show is null ");
        return 0;
    }

    gnome_url_show("file:/root/Desktop/testcase.txt",NULL);
    printf("\n AFter showing console");
    return 0;
}

Therefore this appears to be an issue with the OS call gnome_url_show(). However, this API is deprecated and the issue will not be fixed. We have been advised that gtk_show_uri() should be used instead. The JDK implementation should be modified to use the new API.