windows - Elevate Java application while running

Question

A nasty problem popped out with my software. I am making a program that interacts with another existing software (a game). User has reported that he runs the game with administrator privileges and under that circumstances, my program stops working for him.

Short investigation revealed that some people really need to run the game under administrator account and some don't. It would be great if my program would be able to detect this and warn user if the game is running under administrator account:

If the user clicks "Elevate", I'd like to ask windows to elevate the java.exe running my jar file and invoke the typical UAC dialog.

^{Obviously, this time the question would not be about java updater but JRE}

My question is: Is this possible? Can windows elevate my java.exe instance's privilege? Does java have a way to do it? Or can I use command line command?

I want to avoid restarting the program (though it wouldn't probably be such a big deal).

Edit: If you look in the comments, you'll see that there's no avoiding the restart of an application - process can only start elevated, not become elevated. This kinda shifts the question, unfortunately. Basically, it now sounds more like: "How to restart my application with admin rights?". Unless, of course, there's a trick like two java.exe sharing one jar...

Answer 1

If still of interest: In Windows 7 my JavaElevator works. It elevates a running Java process when used in the main method of the Java application. Simply add -elevate as last program parameter and use the elevator in the main method.

The elevator class:

package test;

import com.sun.jna.Native;
import com.sun.jna.platform.win32.Kernel32;
import com.sun.jna.platform.win32.Kernel32Util;
import com.sun.jna.platform.win32.ShellAPI;
import com.sun.jna.platform.win32.WinDef;

/**
 * Elevates a Java process to administrator rights if requested.
 */
public class JavaElevator {
    /** The program argument indicating the need of being elevated */
    private static final String ELEVATE_ARG = "-elevate";

    /**
     * If requested, elevates the Java process started with the given arguments to administrator level.
     * 
     * @param args The Java program arguments
     * @return The cleaned program arguments
     */
    public static String[] elevate(String[] args) {
        String[] result = args;

        // Check for elevation marker.  
        boolean elevate = false;
        if (args.length > 0) {
            elevate = args[args.length - 1].equals(ELEVATE_ARG);
        }
        if (elevate) {
            // Get the command and remove the elevation marker.
            String command = System.getProperty("sun.java.command");
            command = command.replace(ELEVATE_ARG, "");

            // Get class path and default java home.
            String classPath = System.getProperty("java.class.path");
            String javaHome = System.getProperty("java.home");
            String vm = javaHome + "\bin\java.exe";

            // Check for alternate VM for elevation. Full path to the VM may be passed with: -Delevation.vm=...
            if (System.getProperties().contains("elevation.vm")) {
                vm = System.getProperty("elevation.vm");
            }
            String parameters = "-cp " + classPath;
            parameters += " " + command;
                Shell32.INSTANCE.ShellExecute(null, "runas", vm, parameters, null, 0);

            int lastError = Kernel32.INSTANCE.GetLastError();
            if (lastError != 0) {
                String errorMessage = Kernel32Util.formatMessageFromLastErrorCode(lastError);
                errorMessage += "
  vm: " + vm;
                errorMessage += "
  parameters: " + parameters;
                throw new IllegalStateException("Error performing elevation: " + lastError + ": " + errorMessage);
            }
            System.exit(0);
        }
        return result;
    }
}

Usage in the main method of the Java application:

public static void main(String[] args) {
    String[] args1 = JavaElevator.elevate(args);
    if (args1.length > 0) {
       // Continue as intended.
       ... 

I know, this is a very basic implementation - sufficient for one of my daily hiccups: Starting an elevated process from Eclipse. But maybe it points someone in some dicrection...