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Detect if current user is ADMIN using JNA (Windows) Tag(s): JNA Environment Security


JNA (Java Native Access) provides Java programs easy access to native shared libraries (DLLs on Windows) without writing anything but Java code - no JNI or native code is required.

This HowTo detects if the current user is a member the Administrator group. This is done by checking the "well-known" sid. 

import com.sun.jna.platform.win32.Advapi32Util;

// https://github.com/twall/jna#readme
//    you need 2 jars : jna-3.5.1.jar and platform-3.5.1.jar

public class IsAdmin {
    public static void main(String[] args) {
        boolean isAdmin = false;
        Advapi32Util.Account[] groups = Advapi32Util.getCurrentUserGroups();
        for (Advapi32Util.Account group : groups) {
           if ("S-1-5-32-544".equals(group.sidString)) {
              isAdmin = true;
              break;
           }
        }
        if (isAdmin){
           System.out.println("Current User is ADMIN");
        }
        else{
           System.out.println("Current User is not ADMIN");
        }
    }
}

Instead of hard-coding the well-known string representation of the Administrator group, we can used the Windows API exposed by JNA to verify the value. 

import com.sun.jna.platform.win32.Advapi32;
import com.sun.jna.platform.win32.Advapi32Util;
import com.sun.jna.platform.win32.WinNT.PSIDByReference;
import com.sun.jna.platform.win32.WinNT.WELL_KNOWN_SID_TYPE;

// https://github.com/twall/jna#readme
//    you need 2 jars : jna-3.5.1.jar and platform-3.5.1.jar

public class IsAdmin {
    public static void main(String[] args) {
        boolean isAdmin = false;
        Advapi32Util.Account[] groups = Advapi32Util.getCurrentUserGroups();
        for (Advapi32Util.Account group : groups) {
           PSIDByReference sid = new PSIDByReference();
           Advapi32.INSTANCE.ConvertStringSidToSid(group.sidString, sid);
           if (Advapi32.INSTANCE.IsWellKnownSid(sid.getValue(),
                  WELL_KNOWN_SID_TYPE.WinBuiltinAdministratorsSid)) {
              isAdmin = true;
              break;
           }
        }
        if (isAdmin){
           System.out.println("Current User is ADMIN");
        }
        else{
           System.out.println("Current User is not ADMIN");
        }
    }
}
See also this HowTo.
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